THE XANTHIDAE AND SOME OTHER CRABS

MARINE CRUSTACEANS III By L A THE XANTHIDAE AND SOME OTHER CRABS BoRRADAiLE, M.A., Lecturer in Natural Sciences College, at Sehvy")i Cambridge (With Text-figures 41—60.) The in-stalment of the Marine Crustaceans of new the Expedition described in this paper allied to them, and a couple of Hapalocarcinidae which are taken here for reasons and the small families the Atelecyclidae Some remarks on the natural history of the crabs will be found under the of convenience headings of the families, genera, etc to which they belong includes, besides the Xanthidae, two genera, possibly — — Types of the Xanthid Crabs A Actaea fossulata, resembling water-worn coral pebbles and found in the lower parts of a coral stock or other situations into which pebbles could be washed B CarpiUus exsculptus, Fig 41 C Euxanthus exsculptus var rugosus, found amongst stones, Domoecia hispida, a coral crab F Trapezia ferruginea, also a coral i? is a large crab, C and F of moderate size, and the others small adapted for passively withstanding surf and currents etc on the crab B Chlorodius harhatus E The drawings are not made to scale, reef Family Xanthidae Of all the families of crabs the Xanthidae are the most numerous in genera and species, and the most varied in form, though this preeminence is seen chiefly in the Tropics, and there best in the littoral belt, where they are to be found in every possible position 238 BORRADAILE A L among Morphologically, the Xanthids are characterised, clometopa), by the absence of a rostrum, the the other round-fronted crabs (Cy- sloping or transverse first antennae and short second antennae, the sharp fore edge to the mouth, and the legs of the last pair not adapted for swimming, nor the branchial regions swollen Bionomically they are harder to characterise, but, speaking broadly, we may say that they are not sand crabs, nor swimming crabs, nor land crabs, but essentially crabs of the reef surface and the coral stocks, though some of them may be found in other positions Their division into subfamilies and genera depends on such characters as the shape of the orbits and antennae, and the relationships of these to one another, the leaves on the palate (endostome) which mark out the channels by which water the shape of the body' The species are separated by details ridges the gill-chamber, and such as the shape of the front and the hands, the sculpture and areolation of the carapace, and the presence or absence of spines on the limbs or the sides of the body The body of a typical Xanthid 53, 54), or Carpilius (Fig 41 B), is —a Xantho, an Actaea (Figs 4U., heavy and compact, with a for instance (Fig 50), or of a transversely oval shape, hard cuticle and short legs, which can be folded up close under the body" The chelae are and powerful, and the habits sluggish Such crabs live almost anywhere on the reef sometimes showing a preference for some particular kind of shelter, such as holes usually large or cracks in the rocks, but more often, I think, adapting themselves to any that can be Specimens are thus often taken in coral stocks, though the crabs cannot be said to be characteristically coral crabs, being equally, if not more often, found under stones, which afford the most favourite hiding-place of all some of the larger species are restricted to found ; the reef, but ' of the smaller ones are also to lu the following key the sub-families of the Xanthidae are defined by I many means Endostome of these features ridges wanting broadly in contact shape and : of orbital gap Second joint of anteunal stalk cylindrical, reaching vary in Second joint of antennal stalk somewhat irregular in shape and broadly in contact with the front Endostome ridges strong, and project on the fore edge of the mouth the front but not entering the orbital gap Oziinae Xanthiiuie Front at least B ridges 3Ie)iippinac Flagellum of antenna not shut out Endostome size Shape of the body trans- versely oval or rounded A be found in the lagoon wherever coral Second joint of antennal stalk as in Xanthinae but half, and fronto-orbital edge more than two-thirds the greatest breadth of the carapace Front makes an angle with the antero- entering the orbital gap Cdrpiliiiae lateral edge Flagellum of antenna alwaj's shut out of orbital gap Flagellum of antenna shut out of orbital gap by part B of the second joint of the stalk Endostome ridges strong, and project on the fore edge of the mouth Etixinae Eiiphiijiae n Endostome ridges present Shape of the body often square or squarish Front less than half, and fronto-orbital edge (front and orbits together) not more than two-thirds the greatest breadth of the carapace Front usually A makes an arch with the anterolateral edge Fla- gellum of antenna usually not phut out of orbital gap Second joint of antennal stalk cylindrical, and may or may not reach the front, with which it is not Endostome ridges moderate, and make no projection on the fore edge of the mouth Trapeziiime The genera will be found ranged under these sub-families below The figure (41 c) of Euxanthus exsculptus gives an excelexample of the way in which the limbs are often folded up so as to form with the bodj' a compact mass Fig 47 shows how the legs are sometimes specially shaped for folding - lent into a small compass MARINE CRUSTACEANS The grows to a times at massive, compact form of body and spent in positions where life swimming From this the strong cuticle are, no doubt, adaptations they are surrounded with hard, stony objects, and exposed and strong currents, and at others surf to escape by 239 enemies which they are unable to to like the Portunidae typical body-form there deviations course, of are, Such genera which a few only can be mentioned here in various directions, as Chlorodius (Fig 41 1)) dozius (Fig 45) are flatter and lighter built, with longer legs, though the cuticle is of and Pseustill strong, and they are more often to be found in situations like the interstices of coral stocks, where they must maintain their position by the use of their limbs, rather than by their weight or by wedging themselves fast, like the heavier genera Yet even these' are far from being true coral restricted crabs, to the living jjarts of the stock, Melia (Fig like 49), Bomecia the Trapeziinae (Figs 41 F, 58), on which some remarks will be found below- Another very characteristic habitus is that of Pilumnus (Figs 46 48), slightly built, very (Fig 41 E), or — and often with squarish, rather than hairy, As to the meaning of the numerous, and often very Xanthids are distinguished in Why, and detail, it for instance, are the species of (Figs 53, 54) ? oval, bodies, falling And why these is as yet very steeply in front beautiful, features by which the impossible, in most cases, to say anything Actaea bejewelled with the most beautiful pearly granules granules become sharp flatten themselves into leaflets in others (Fig 55) thorns in some species (Fig 56), should the back of Euxanthus Why i rough and uneven, or that of Carpilius (Fig 41 B) glassy smooth ? Why is Liomera barrel-shaped (Fig 52) and Pseudozius often as flat as a board (Figs 43, 44)? Before these questions can be answered, much more must be known about the habits of the crabs We may, however, indicate some directions in which it will be well to look (Fig 41 C) be The texture answer the for of the back and and legs, their nakedness or hairiness, will perhaps be found to depend on the necessity of friction with the surrounding objects when the animal wedges itself firmly into its hiding-place, or of presenting a smooth surface to waves and currents, so that they may pass over the animal without sweeping it away; or again to the need of disguise, either by a covering of fine silt, held by hairs or bristles (often a very effectual device) or by adherent organisms which will not grow on a smooth surface, or even [Actaea cavipes and fossulata (Fig 41.4)] by a likeness to water- worn pebbles of coral The shape of the hands may be adapted to the food, or to defence against some enemy, or special The remarkable may Atya the correspondence with that of in the some front may — to breathing serve to give their owner a foothold among of the way ' pra\vn in need of keeping open a way for And lastly the shape of the end-joints of the walking Except, probably, P coralliophilus and P triunguicu- 241 fingers of the which the antennae are used, and on the breathing stream, a function which it shares with front depends on the the chelipeds'' latiis (p foreign the rough coral branches, gather food in some special way, like the tufted, spoon-like The shape among seems to be a sexual character which turn up again and again in cases hoof-like ends to the fingers (Fig 57 C), genera', different or — in of various grades of coarseness', or particles S.) than below it has yet received (p legs, which shows a of it, mentioned arrangement at the end of the Of course the closure of the orbital gap has Another instance 242), is the pulley - pp 249, 263 walking ' Garstang, Q J M S XL p 211 This phenomenon of the occurrence of the same feature happened over and over again in various groups of Crabs, and the loss of the mandibular palp and the epipodites among Prawns is a similar case ' in groups which cannot be related to one another is not Decapods, and is worthy of more attention legs uncommon among G 31 240 L BORllADAILE A very great diversity, will be found, I believe, to be connected with the nature of the ground on which fast the animal's and stocks, coral with to life its is passed, whether habits, whether it live crouch it among stones or in sandy places or in with folded limbs under shelter or hold legs its A Tip of Ends of the walking legs of Xanthid Crabs Same part in Trapezia ferruginea (Fig 41 F) C Whole being much less enlarged than iS or C not made to scale, Fig 42 B tbe end-joint end-joint in Cnrpilius in convexus Actaea speciosa (Fig 41 A) The drawings are -1 A may be found in the illustrations scattered through accompanying figure (Fig 42) three of the most unlike of the present paper, but in the Carpilius convexus is a heavy-bodied, spindle-shanked crab, too them are shown enlarged big and clumsy to climb among the branches of coral stocks, which leads a sluggish and uneventful life among objects on the bottom, and has even been found enclosed as in a number of examples of this feature cage by the growth of coraP ferruginea ending of meaning speciosa guessed its of Its legs {A) accordingly end in a very simple claw Trnpezia we may suppose that the remarkable But what can be the some way connected with this fact a typical crab of the living coral, and is legs (B) the curious is in brush of at hairs the end of (C), and why this structure is not found on the Some remarks on the different ways in which to that before it will be found below on p the first walking leg of Actaea other legs, cannot as yet be even the last joint may be hinged on 242 According to Henderson [Tr Linn Soc Zuol (2) V p 332] the colour markings of shore Decapoda are generally protective in their nature, but this is certainly not always the case, as, f)r instance, in Trapezia and Carpilodes to In another respect, besides those of structure and habits, the Xanthids offer a contrast swimming crabs, described in the last number of this publication, which, next to the them, are the most conspicuous family of crabs in the Tropics They are, with some striking In the Trapeziinae, exceptions, not very variable, and are not varietal, save in a few cases of constituremarkable plasticit}' genus Piliimnus shows a however, varieties appear, and the tion, which leads to the formation of numerous local species and will be alluded to again below ^ Coutiere, Bull Mas hist, iiat., 1898, 5, p 238 - P- 244 — " 241 MARINE CRUSTACEANS Subfamily Menippinae Genus Pseudoziiis Dana, 1851 Pseudozius dispar Dana, 1852 Pseudozius dispar, Caiman, Tr Linn Soc (2) The granular field 14 (1900)i viii p on the larger hand of the male of this species grows relatively smaller with age Taken on the reef Miladumadulu Atoll Male, in Goifurfehendu and Fadifolu Alcock, Pseudozius caystrus (Ad and Wh.), 1848 This common very species, certainly occurs at Minikoi, which is ill Atolls, p though unfortunately no specimens of in Funadu Vein, 181 by Alcock from recorded and the Laccadives, almost have reached England- it b Limbs Fig 43 of Pseudozius coralliophilnx; a outside of greater haud, Pseudozius coralliophilus, Diagnosis " : A lateral lobes, walking leg, c, d end of the same enlarged sp (Fig 43) Pseudoziiis with the carapace finely granular, bearing a few scattered hairs, the marked out the fuiTow between the the regions faintly rounded n l> ; front front sloping gradually and the edge with three very low humj)s, from the on the back; the chelipeds unequal, of which last finely granular, their hand, furrowed and subcylindrical, with downwards, cleft into orbit ending on a small lobe ; two low, the antero- a fine ridge runs inwards fingers widely gaping, especially on few isolated blunt teeth, the arm and wrist (meropodite and carpopodite of the cheliped) without spines, the fore edge of the arm finely toothed and the walking legs fairly stout, with a long end-claw the large a ; Length : mm Breadth : mm Colour in spirit : cream, with pale brown, cream-tipped fingers A single male specimen was taken from a block of the brain-coral Leptoria tenuis growing Minikoi It was sheltering at the bottom of one of the holes in the coral in the lagoon at made by another Whether the first owner of the hole had been ousted by the Pseudozius there was nothing to show, nor can we tell as yet whether the latter lives always in Cryptochiru,s-h.o\es or had merely retreated into one in this case as the water drained off the surface of the coral In another of these holes there was found a female Pseudozius, sheltering in the same way, and it was had ^ little crab Cryptochirus coralliodytes^ died, or left willingly, or Wbere synonyms will be found which references are given For the principle on in this paper see p 192 of Part II - See footnote to p 191 of Part '' See below, p 271 II of this publication, of the present publication 31—2 242 A L BORRADAILE at first that this was the female of the crab whose male we have just Further examination, however, showed differences between the two so great that they must belong to different species The second specimen is described below under the name natural to suppose described of P triunguiculatus I am much obliged to Mr Edwin Wilson, F.E.S., for calling my attention to a very in- — d) As usual, the teresting structure which he discovered on the legs of this crab (Fig 43 b the one the end of before it last joint (dactylopodite, end-joint) is held in a deep notch at (propodite) But in the present case it bears on the hinder side a flange, and a knob, which works in a groove on the propodite small pit, into which the knob slips when the joint At the inner end is fully flexed, so on the flange of this that the groove is end-joint a is held firm in this position, thus providing the crab with a hook, by which, no doubt, it keeps P triunguiculatus has a less perfect form of the same apparatus its position on the coral (Fig 44 c) Fig 44 it, In it, the flange on the last joint works against a special process of the one before Pseudozius truingtiiculatits, symbiotic with a coral; a whole animal, b outside of greater hand, c hinder side of end of walking leg, d fore side of the same but this process has only a smooth surface and no podite seems placed in this position to prevent gi-oove A small spine under the pro- the end-joint from being unduly flexed, and no doubt the other spines give a foothold to the animal On the whole, these structures, as well as the general appearance of the body and limbs, give the impression that the crabs are indeed symbiotic with the coral, living always on its surface, but take refuge in the Cryptochirus holes at times only Interestingly enough, the same structure, in its simpler form of a flange on the end-joint working along a smooth path on the joint before it, turns up again in the coral crabs of the Trapeziinae and in Domecia, though not in Melia, which crooks the whole leg and not the last joints only, and is also present in Chlorodopsis (Fig 57 c) and Phymodius, which, without MARINE CRUSTACEANS 243 being true coral crabs, are often found in coral stocks, and in the Actaeas of the flosculatawhose habits as yet nothing is kno\vn, since they have only been taken with the gi'oup, of Actaea speciosa (Fig 42 O) dredge The found object of the an example of a species in which the flange is is not no doubt, to enable the end-joint to be moved more in any position and it is only an elaboration of structures apparatus evenly and accurately and held fast is, ; found in most crabs, which have usually a small facet on the hinder side of the last joint for the end of the propodite Its absence is, nevertheless, particularly interesting in the case of Eriphia, which is allied to Doniecia, and of Pseudozius other than the two species mentioned A single glance at the orbits of these latter species is enough to show that they have no place among the Trapeziinae, Eriphiinae, or Etisinae, so that the formation of the legs in question must have arisen, like so many other chai-acters of the crabs, independently in two above or more cases^ It is probably an adaptation to clambering Pseudozius triunguiculatus, Diagnosis " : A n sp (Fig the regions not marked out hairless, 44) Pseudozius with the carapace smooth (microscopically roughened) and flat, the front sloping slightly downwards, standing well forward ; beyond the eyes, with a wide shallow bight instead of the usual notch in the middle, no side the anterolateral edge with three low, blunt teeth, the lobes, and a shallow median furrow hindermost of which is hardly distinguishable the chelipeds, large, unequal, covered with granules of some size, which are largest on the upper part of the outside of the hand, no spines on the ; ; arm or wrist, the fingers flattened, not gaping, sharply pointed at the tips, in the large the fingers set, hand on their opposed edges, with a row each of conical teeth, in the small hand making up a remarkable pair of shears, which are no doubt adapted and the walking legs rather slender, each bearing on its of three slender, brown end-claws, of which two are somewhat smaller than these edges blade-like, to some peculiarity a set last joint in the habits ; the third." Length : mm Breadth : mm Colour in spirit : pale brown, the walking legs white, the back covered with small dark-brown spots, the fingers white One female specimen taken on Leptoria tenuis in Minikoi lagoon Subgenus Platyozius, A specimen dredged in Suvadiva cannot be refeiTed to any known species, and difficult to point, but and it n is place in a genus none of these is It differs from Pseudozius, as hitherto defined, in of importance enough up to warrant the setting new subgenus therefore taken here as the type of a is also more than one new genus, of a Other groups of Platyozius species akin to Pseudozius will probably have to be reduced to this rank before long Platyozius differs from Pseudozius fronto-orbital breadth chelipeds endostome (4) (2) s str the in following points: Absence of small outer lobes from the Slenderness of the legs (.5) A flatter front (1) Relatively greater (3) and shallower body Equality of the (6) Less marked ridges Pseudozius {Platyozius) Diagnosis " : A laevis, n sp (Fig 45) Platyozius with the carapace smooth, hairless, without regions ; the front broad, bent slightly downward, almost straight, with a broad shallow bight in the middle and See above, footnote to p 239 ; 244 L A BORRADAILE notches separating it from the orbits, but no outer lobes the anterolateral edges short, with two big blunt triangular teeth behind the orbital angle, and a small notch, rather than a projecting tooth, at the junction with the posterolateral edge the hinder edge slightly hollowed the chelipeds equal, smooth, without spines but with a blunt tooth at the inner angle of the ; ; Fig 45 Pseudozins laevis; a whole animal, wrist, the fingers compressed, grooved, not gaping, each and the walking locking with those of the other; b outside of hand with a row of triangular teeth inter- legs long, slender, sparsely hairy, out spines, except on the dactylopodite of the last which leg, and with- rather broad, while those is of the other walking legs are very long and narrow." Length : mm Breadth : One male specimen dredged mm Colour in spirit in 20 fathoms in white : Suvadiva Atoll Genus Pilumnus, Leach, 1815 As a general in environment There freshwater crabs of the tions, as evident but are spread over rule the species of crabs are not local in distribution, wide areas and are probably correlated with habitative are, of course, exceptions to rather than ' this genera Sesarma and Potamon rule, as for Pilumnus is geographical diiferences instance the land and another of these excep- may be seen at once on looking down a list of the known species, when it will be many of them have been only recorded from one locality This impression is that strengthened on reading the remarks of various authors in recording a species from a new locality In many cases the identification that of the original specimens is The present doubtful, or the description does not tally with collection affords an excellent example of this, not one of the 11 species being represented by specimens which exactly obey former diagnoses Under the circumstances closely with ' specific For the meaning of this publication I shall de.scriptions describe as new species already published, and this word, see p 195 of Part II of - the forms which not agree rank as subspecies'- those which in- See footnote to p 195 of Part II of this publication : MARINE CRUSTACEANS The phenomenon fringe such descriptions in small points only deserves, 245 of local variation in Pilumnus and would repay, careful investigation, especially with number intermediates, their relative to of the those described regard to the existence of forms, and their distribution, whether they be found in intermediate localities or no In short, information is needed as to whether the subspecies of Pilumnus be " discontinuous," like true varieties, or no The members Pilumnus The of the genus live under stones, in coral blocks, etc Maldive specimens fur of the is III.' p 192 not dark, as in the type, but of a golden-yellow Karachi and Tavoy colour, like that of Alcock's race At the same time the usual smooth patch be found near the base of the finger of the large hand to is Alcock, vespertilio (Fabr.) 1793 Perhaps these characters are distinctive of local races or subspecies of P vespertilio The species, which sluggish is in the reef at Hulule, Male Atoll, and in its habits, lives Pilumnus andersoni de Man, 1887 The Maldive specimens See Alcock, subsp.^ There are no granules on the carapace, which (2) The there on the the same arrangement as the type it spines at of the is vestigial, and on the fore spines Alcock does not mention presumable that specimens presented all his In the Maldive example there growing smaller from without inwards arched, sharp 194 p everywhere smooth and finely pitted The arrangement the arm does not agree with that described by de Man edge of is a row of strong, blunt In de Man's specimens there were two, large, the outer end, with a small spine at the base of the distal of the The more proximal was two is (3) these spines, but, as he cites de Man's paper, teeth, ill edge of the meropodites of the walking legs are fore no spine at the end of the joint is and was taken on etc., from the race defined by Alcock in the following points differ (1) spines under stones, Funadu Velu, Miladumadulu larger than the distal one, and behind it were four or five acute granules Dredged in —39 fathoms in Minikoi, South Nilandu, and Haddumati Atolls Pilumnus hirsutus Stimps, The Maldive specimens following points: (1) A 18.58 See Alcock, subsp in p 197 from those on which Alcock's description was founded in the is present (2) The gaps on the orbital edge differ small subhepatic tooth are fairly distinct According to Haswell {Cat Austral Crust, p 69), the meropodites of the walking legs of this species should bear three or four spines Alcock does not mention these spines, and they are wanting in the Maldive specimens, in which the fore edge of the meropodite is roughened by a row of low, blunt teeth Alcock is doubtful about the identity of the species he is describing as P hirsutus, and A single rather less seems likely that the three forms points " full." : (1) (3) — I Part II p 192 of the present publication ^ See footnote to p 195 of Part ' I am are -distinct using the word "form" II differs The antennal flagella are long and hairy The body is rather flatter (4) The legs ' Journ As Soc Beng lxvii ii 233 (1898) For pp 67 the principle on which references are given in this paper see Vol ' specimen from South Nilandu, which bears a Sacculina, in the following is it of this publication in its broadest sense to from the others (2) 'The large are a include species, subspecies, and varieties little hand longer In this sense it "group," used to include all divisions of the animal kingdom from genera upwards For definition of " variety " and " subspecies " see the article on is a useful counterpart of Varieties in Part II of this publication 246 It L impossible to say whether any or is A all BORRADAILE of these features be due to the presence of the parasite The figure of a specimen referred to this species in the P.Z.S for 1900 [pi XLii., fig 9] was drawn with the hair on the body and in consequence the side-teeth and frontal notch have not been shown by the artist Dredged 22 in — 45 fathoms in Haddumati, Felidu, Addu, Mulaku, North Male, South Nilandu, Suvadiva, and Kolumadulu Atolls Fio 46 Pilumnus rotundus, " Diagnosis : A ; n sp (Fig a whole animal, outside of hand h 46) Pihuiihus with the carapace very convex, subglobular, covered with short hairs, the regions faintly granular edge Pihimmis rottindus; marked ; the lobes of the front only moderately prominent, with faintly the lower rim of the orbit denticulate, the upper rim granular, with two distinct but shallow notches; the anterolateral edge bearing four spiniform teeth, of which the first is the orbital angle, the teeth being short and set wide apart and having smaller teeth at their bases ; the chelipeds rather unequal, covered outside with stout thorns, which are arranged in somewhat irregular rows and are largest on the upper side, the fingers the hand, the moveable finger bearing a strong ridge above long, covered with at the ; bent at an angle with and the walking legs moderately long hairs, and with a thorn on the upper edge of the meropodite and one end of both the meropodite and the carpopodite." Length: mm Dredged 10 in Breadth: 12 mm Colour in sjiirit : yellowish-white, with white fingers 35 fathoms in Kolumadulu Atoll Pilumnus do7-sipes Stimps, 1858 The specimens agree very Alcock, ill p 197 closely with Alcock 's definition, but I am quite unable to detect MARINE CRUSTACEANS furrow is be seen by comparing the figures different, as will Actaea splnosissinia Fig 55 257 ; whole animal, a b (4) outside of hand, c The peculiar tubercles on end of walking leg enlarged the outside of the hand of A fimcidata are replaced in A spinosissima by sharp thorns, and the teeth on the apposed edges of the fingers are less stout." Length : Dredged mm Breadth Mahlos in Diagnosis " : An 5-2 Atoll, in Actaea perspinosa, 43 : mm Colour in spirit : white 23 fathoms n sp (Fig 56) Actaea nearly akin to A Jlosculata, but differing from it in that, in place of the characteristic petaloid spines of the latter species, it is "^) covered with stout, sharp thorns of an entirely different shape." From A in spinosi'ssinia it differs the points indicated above, and from A acantha A.-M Edw., 1861, and A hystrix Miers, 1886, in the gi-eater size and smaller number of the spines Length: Colour in mm spirit Dredged in : Breadth: 55 mm a pure white Miladumadulu Atoll Fig 56 in 25 fathoms c 44 1859 a whole animal, b outside of hand, end of walking leg enlarged Actaea perspinosa ; Actaea fossulata (Girard), Alcock, The bridge III p 148 (Fig 41 A.) across the hollow on the carpopodites of the walking legs Taken on the reef at Hulule, Male Atoll, and in is not always to be found Funadu Velu, Miladumadulu 33—2 258 L- Actaea cavipes (Dana), 1852 45 BORRADAILE A Alcock, in the lagoon at Minikoi, in Dredged — p 147 ill fathoms Genus Daira de Haan, 1833 Alcock, (Hbst.), 1790 Daira perlata 46 Taken on the shore p 155 iii and Goifurfehendu in Minikoi Genus Lophozozymus A Dredged in fathoms in Male M.-Edvv., 1863 Alcock, Lophozozymus dodone (Hbst.), 1801 47 Atolls iii 108 p Atoll Genus Zozimtts Leach, 1818 Zozimus aeneus 48 Taken on the shore Alcock, (Linn.), 1764 in Male and Minikoi iii p 164 Atolls Genus Lophactaea A M.-Edw., 1862 Alcock, in Lophactaea anaglypta (Heller), 1861 49 Taken on the reef at Hulule, Male Taken in Funadu Velu, Miladumadulu Alcock, in p 100 Atoll Lophactaea fissa Henderson (1893) 51 102 Atoll Lophactaea cristata A M.-Edw., 1865 50 p Alcock, in p 103 Alcock seems to have overlooked the fact that, besides the wide gaps in the side edge is separated from L granulosa by the presence of a thick coating of the carapace, this species of long yellow hairs not shown scribes in No doubt because this coating hides the granules of the carapace it is v., pi XXXV fig 8), though he de- Henderson's figure (Tr Linn Soc Zool it Taken on the 52 Alcock, Lophactaea granulosa (Rlippell), 1830 Dredged 53 reef at Goidu, Goifurfehendu Atoll in Felidu and South Male in p 101 Atolls Lophactaea semigranosa (Heller), 1861 Taken ill Funadu Velu, Miladumadulu Alcock, in p 101 Atoll Genus Atergatis de Haan, 1833 54 Atergatis floridus (Rumph) Taken on the reef at Hulule, Alcock, in Male Atoll, p 98 under stones MARINE CRUSTACEANS 259 Subfamily Carpilinae Genus Phymodius A M.-Edw., 1863 Phymodius ungulatus (H M.-Edw.), 1834 5.5 Phymodius ungulatus, Ortmann, Zool Jahrb Syst vii p 464 (1893); Alcock, ill p 162 (1898) Phymodius monticulosus, Alcock, I am either of quite unable them to ill p 163 (1898) distinguish between rather than to the other these or to species, my assign All the characters vary, as specimens to seems independently, it and the descriptions given by several authors not always agree Until examination of a long series of full-gi-own males have shown whether there exist varieties corresponding to the above two names, and if so exactly in what points they differ, I prefer to follow Ortmann in joining the species absolutely, without keeping varietal names These which were taken on the reef in Hulule and Goifurfehendu Atolls and in live in coral stocks and under crabs, lagoons in —7 fathoms in Minikoi and Miladumadulu Atolls, stones 56 Phymodius Taken on the sculptus (A M.-Edw.), 1873 reef in Alcock, Male and Goifurfehendu iii 164 p Atolls Genus Chlorodius H M.-Edw., 1834 The members 57 of this genus are often found in coral stocks Chlorodius laevissimus Dana, 1852 Alcock, p 161 iii In one specimen the teeth on the inner side of the fingers are wanting in the small chela and obsolescent Mahlos Atolls 58 in The in the large Taken on the reef in 22—25 colour of many specimens Goidu and Fadifolu Chlorodius barbatus Borradaile, 1900 Taken on the reef, and Miladumadulu Atolls reef yellow, rather than white South Nilandu in and fathoms (Fig 41 D.) Chlorodius barbatus, Borradaile, Proc Zool Soc 1900, 59 is and dredged Atolls, in lagoons down Chlorodius niger (Forsk.), 1775 to Alcock, p 587, fathoms, iii in pi xli fig Minikoi, (1900) Goifurfehendu, and p 160 Taken in Male, Fadifolu, Goifurfehendu, Felidu, North Male, and Minikoi and in lagoons down to 25 fathoms Atolls on the Genus Euaanthus Dana, 1851 60 Euxanthus exsculptus Euxanthus melissa, Alcock, (Hbst.), 1790; var rugvsus Miers 1884 (Fig 41 C.) in p 110 Since Miers speaks of a specimen of some size, it is likely that this is at least a variety, 260 A L BORKADAILE I am inclined to think that it will prove to be a distinct and not merely a young form The specimen before me measures 14 mm in length and 21 in breadth The brown species Taken on the reef at Hulule, Male Atoll colour of the fingers does not spread over the palm Genus Garpilodes Dana, 1851 Caiyilodes stimpsoni, A M.-Edw., 1865 61 Taken on the Garpilodes pediger Ale, 1898 Alcock, ? Two small male specimens in the collection G ruber and Fadifolu Atolls 63 The in colour is ill p 83 may young They were dredged either be the that of G pediger in 25 or Miladumadulu Taken on the 228, p pi xi fig (1865) fathoms in South Nilandu Atoll Garpilodes vaillantianus (A M.-Edw.), 1862 Minikoi lagoon reef in Male and Goifurfehendu Alcock, Atolls, in III p 85 Funadu Velu, Miladumadulu, and In the latter locality a specimen was found among the Halimeda-weed, where 65 in Garpilodes ruber A M.-Edw., 1865 Dredged in of this species 20 and 23 fathoms respectively Garpilodes ruber, A Milne-Edwards, Norm Arch Mus 64 p 82 ill reef at Goidu, Goifurfehendu Atoll 62 belong to Alcock, its leaflets of the bright red colour could not be in the least protective Garpilodes monticulosus A M.-Edw., 1873 Alcock, iii p 86 This species, which lives under stones, was taken on the reef at Male, Goifurfehendu, and Minikoi Atolls 66 Garpilodes pallidus Borradaile, 1900 Garpilodes pallidus, Borradaile, Proc Zool Soc 1900, This species that: (1) There is is 586, pi XL fig allied to G monticulosus and to G cariosus It differs from the former in no narrow transverse ridge behind the mesogastric lobule (2) The furrows of the carapace are not so deep From p (3) The colouring is quite different The lobules are not pitted, and the carapace has There is no transverse ridge behind the mesogastric (2) lobule, and the branchial lobules are not broken up into smaller ones (3) The furrows between the lobules are rather shallow (4) Counting the groove which marks off the mesogastric lobule and that which runs within the hinder edge, there are altogether three grooves behind the lobule in question, but the middle of the three is shallow, and may consist of two separate dimples, hardly connected across the middle line (5) The notch between the first two lobules of the edge may be rather indistinct (6) The pink colour of the legs does not tend to orange (as in most of my specimens of G cariosus), and even in the most brightly G cariosus it differs in that: (1) therefore not a worm-eaten appearance coloured specimens there Taken on the is no trace of colour on the carapace reef at Hulule, Male Atoll MARINE CRUSTACEANS Carpilodes cariosus Ale, 1898 67 Alcock, iii 261 p 86 One small male from The colour in most of my specimens is Miladumadulu, however, exactly agrees with Alcock's description of the colouring, and at the same time differs from the yellow-marked specimens in having less extensive patches of colour not pink but orange-yellow \ on the back, and in that the lobules of irregular in shape It is possible its that this is carapace are somewhat more compact and less the true C cariosus, while the other specimens belong either to a distinct species or to a variety Dredged 20 in — 40 Miladumadulu, Suvadiva, Mahlos, Fadifolu, Male, and South Nilandu in Genus Carpilius Desm., Carpilius maculatus (Linn.), 1764 68 Atolls, fathoms Alcock, 182.5 p 79 III This species was seen both at Minikoi and in the Maldives It may be found wedged into holes on the reef just above low water-mark, exposed to the full force of the surf Carpilius convexus (Forsk.), 1775 69 Taken in Fadifolu, Male, Minikoi Alcock, iii 80 (Fig 41 B, 42 A) p and North Male Atolls on the reef and in lagoons down to 35 fathoms Subfamily Etisinae Genus Chlorodopsis A M.-Edw., 1873 Chlorodopsis spinipes (Heller), 1861 70 Taken on the reef in Male and Minikoi iii p 169 Alcock, in p 171 Atolls Chlorodopsis woodmasoni Ale, 1898 71 Alcock, Taken on the reef in Male, Fadifolu and Goifurfehendu Male Atoll in and dredged in fathoms Chlorodopsis frontalis (Dana), 1852 72 Atolls, Etisodes frontalis, Dana U.S Expl Expd [Not Etisodes frontalis, H M.-Edw., 1834, juv.] The following (1) The i p 187, Bori-adaile, P7'oc Zool Soc 1900, p collection contains specimens of a crab points: Crust, forepart of pi IX fig 588 (1900) (1852) = Leptodius which resembles Dana's species in the carapace derives its sanguineus all but the roughness, not from minute (2) The carapace is a little broader than in Dana's figure are not entii-ely " unaiTned," for the wrist bears two blunt teeth on the inside granules, but from minute dimples (3) The chelipeds The fore front the carapace I a and the upper edges of the little is very little The The length of legs of the last four pairs are finely toothed edge of the meropodite of the third maxilliped is but slightly hollowed more than f of the breadth have placed this species in the genus Chlorodopsis because the fronto-orbital breadth the meropodite of the third maxilliped is and because of the outline of the fore edge of The front is not broad enough to justify its being mo7-e than half the greatest breadth, C vailliantianus also often tends to orange rather than crimson, when preserved in spirit 262 A L- BORBADAILE placed in the subgenus Cyclodius, being less than breadth of the carapace half the In any case the species seems to be a transitional one The specimens mentioned under the name of this species P Z S for 1900 in the were small individuals of Leptodius sanguiiieus reef on Taken on the Male Atoll and dredged Chlorodopsis espinosus; a whole animal, Fig 57 73 Chlorodopsis espinosus, Diagnosis hairless, of : " A like ; five c ends of fingers to show hoof-like (Fig 57) n sp Chlorodopsis whose in length just is the middle, with sharp teeth (including the orbital the hinder edge slightly arched of the basal joint of the antenna is tips, leg enlarged under f of the breadth, the carapace C frontalis (Dana) the front even surface but minutely granular, areolated as in slightly arched, slightly notched with fathoms in South Nilandu Atoll outside of hand, b end of walking d in 25 ; of which angle), the orbital ; thickened edge the ; edge anterolateral two hindei-most are thorn- the gap very narrow, so that the prolongation hard to see; the fore edge of the meropodite of the third maxilliped only slightly concave, with a small projection at without tubercles or thorns except one shai-p inner end its ; the chelipeds equal, thorn at the inner angle of the wrist, the hand narrow, with a faint groove above and a groove down each finger, the fingers long as the fis upper edge of the palm, gaping, with a few sharpish teeth and hoof-like ends; and the walking legs hairy, with spines on the end-joints, and a double end-claw." Length mm Breadth brown with white tips : : 12 mm (Largest specimen.) Colour in spirit : white ; the fingers This species differs fi-om most Chlorodopsis in the absence of spines fi:om the back and chelipeds Taken in 74 Chlorodopsis (Cyclodius) ornata Dana, 1852 ? Funadu Velu, Miladumadulu Atoll I have assigned several small specimens are not really the young of to Phymodius imgulatus this Alcock, species, ill but p am They agree with 171 uncertain whether they Alcock's definition, except MARINE CRUSTACEANS the basal joint of the antenna does in that not placed at its not 263 the orbital gap, though fill apex, a small process extending inwards towards the orbit as figure {U S Expl Taken on the Expd the flagellum shown is in Dana's Crust Atlas, PI xii figs, lie, 11 d) reef in Male, Goifurfehendu and South Mahlos Atolls Genus Etisodes Dana, 1851 Etisodes anaglyptus (H M.-Edw.), 1884 75 Taken on the iii 133 p reef in Goifurfehendu Atoll and dredged in Etisodes electra (Hbst.), 1801 76 Alcock, —9 fathoms in Minikoi lagoon Alcock, in p 133 In young specimens the lobes of the front are shorter, and not so equal as in old individuals, I doubt the specific distinctness of the middle lobes being distinctly broader than the outer this form from E anaglypta Taken on reefs and in lagoons in Male, Goifurfehendu, Miladumadulu, Fadifolu and Mini- koi Atolls Genus Etisus H M.-Edw., 1834 Etisus laevimanus Randall, 1839 77 Alcock, iii p 131 — — Alcock quotes only figures a b on Dana's plate X., seeming thus to exclude figs f which Dana labels as young females of the same species My specimen, a female, exactly sembles these latter figures Taken on the reef at Hulule, Male h, re- Atoll Subfamily Eriphiinae Genus Domecia Eyd and Domecia hispida Eyd and Soul, 1841 78 My var Soul., 1841 (Fig 41 e.) ? See Alcock, iii p 230 specimens agree with the figures and descriptions of B hispida, but have no hairs on the carapace This is It corals a true coral crab, like Trapezia and Melia, and lives was taken on the reef at Goidu, Goifurfehendu Genus Eriphia 79 Eriphia laevimana Latr., 1817 Alcock, Atoll, among and seen the branches of living also in Minikoi Latr., 1817 iii p 214 This species, which was taken at Minikoi, lives in holes in the rocks and in its is rather active movements 80 Eriphia scabricula Dana, 1852 Taken on the reef in Minikoi Alcock, and Addu III Atolls p 216 Lives under stones and in coral stocks Subfamily Trapeziinae This group of cuticle (Figs 41 G f, little, square-bodied crabs, with a broad front and a smooth, usually polished, 56), is very characteristic of the Indopacific region, to which its members 34 264 A L BORRADAILE They find shelter are restricted, and within which they are everywhere abundant on coral reefs on various sessile animals, especially branched corals, from which they are usually not to be dislodged except by breaking up the stock, and it is very remarkable that they are found only on living corals, and in these only on those branches which are still alive Yet they not way damage eat or in any their host, contenting themselves with deriving protection from its In correspondence with this habitat, their legs are rather slender, and have end-joints which can be moved through a considerable arc, so as to form with the next joint a kind of hook, serviceable for grappling the branches of the host These end-joints (Figs 42 B, 58 c) are remarkable and interesting structures when the habitat of the crabs is borne in stinging-cells' working on the joint before, which has been described Besides the peculiar flange mind and is probably an adaptation to clambering, there are several other modifications, which seem intended to give the animals a better foothold on the rugged and yet Thus the joint is covered with hairs, and among these are a slimy surface of the coral The claw at the end of the joint is bent sharply forming prickles number of stout, moveable a hook, and is smooth and pointed in Quadrella, while in Trapezia it is broad and shovellike, and bears above two rows of structures resembling the prickles but rounded at the end It is likely that the smoothness of the bodies of these crabs is due to the same cause as that of other semiparasitic Decapods, such as the mussel-prawns and crabs (Pontonia and above on p 242, and that Pinnotheres), cause this is the need of inconveniencing as has been taken on Alcyonarians of various kinds, and even The Trapeziinae are exceptional and present the varieties, little Trapezia and Tetralia especially affect animals which give them shelter among among Xanthids on account the but Quadrella pearl-mussels" of their feature, unusual in crabs, of definite colour forms some of these forms may be physiological phenomena possible as corals, tendency to form It is possible that same kind as the colour-phases and cannot well be of this nature of the of prawns^, but others are associated with structural features, no relation to the colour of the coral For the present it were well that none of them were overlooked, and I have therefore revived, in two cases, colour names which had been dropped, without, however, intending any implicaIt is also important to note that, in Trapezia, they bear tion as to the nature of the The synonymy Ortmann, of this phenomena group is extremely intricate, and the authority followed here in his late revision [^Zool Jahrh Si/st x Genus Trapezia 81 On p is 201 (1897)] Latr., 1825 Trapezia ferruginea Latr., 1825 (Fig 41 F, 42 B) Var typica Ortm., 1897, Alcock, i ii reefs and lagoons in down to 220 ill p 35 fathoms in Goifurfehendu, Male, Fadifolu, Addu, Minikoi, South Nilandu, Suvadiva, and South Male Atolls ' Mr ii Var dentata (Mackay), 1838 On reefs at Male, I am much From obliged both to first stocks were broken and Mr Stanley Gardiner and to in to last a very large up by loc cit p 204 Goifurfehendu and Fadifolu Atolls and in Suvadiva lagoon in 25 fathoms Forster Cooper for information confirnnng ments Ortmann, the members tliese state- number among the living branches, nor was there any evidence of damage to the coral caused by them of coral - Smith, Proc ISoston Soc Nat Hist of the expedition, ' Gamble and Keeble, Q none of these were Trapezius found anvwhere but J M xii p 288 (1869) S XLtii Pt MARINE CRUSTACEANS On 221 p to 25 fathoms iv Var muculata (Mackay), 1838 On the reefs in Alcock, in p 221 Male, Goifurfehendu, and South Nilandu down at Suvadiva The name the T blue and Atolls, in the lagoons Alcock, iii 219 p coendea was given by Heller in 1861 to specimens of this species in found to a greater or less extent in many individuals, was very tinge, The intermediate conspicuous and Minikoi Fadifolu to 25 fathoms Trapezia cymodoce (Hbst.), 1801 82 which ill the reef in Goifurfehendu and in the lagoons of Mahlos, Suvadiva and North Male down Atolls Alcock, Var guttata Rlippell, 1830 iii 265 which blue ijredominates, are however, between pure brown examples and those in cases, numerous, and form such a complete so series, that it is im- possible to keep coendea even as a varietal name On reefs and in lagoons down South Nilandu, Suvadiva and Felidu Trapezia digitalis Latr., 1825 83 typica A^'ar i to = 35 fathoms in Male, Minikoi, Goifurfehendu, Fadifolu, Atolls T digitalis, Alcock, Ortmann, III p loc cit 222 Dark-brown specimens Taken on the ii reef at Goidu, Goifurfehendu Atoll This variety differs so sharply a separate varietal name T J-erruginea in the The name earliest 1856, is {Proc Bost Soc N H Var formosa Smith, 1869 from the dark-brown true digitalis that In structure the variety shape of the for Xil p 286.) front is like digitalis, but it it seems to deserve somewhat resembles This feature, however, varies considerably in the orange-coloured form is formosa Smith digitalis T corallina Gerstaecker, a coral-red crab Trapezia rufopunctata (Hbst.), 1790 84 Taken on the reef in Alcock, Male and Fadifolu p 222 iii Atolls, and in 19 fathoms in South Nilandu lagoon Genus Tetralia Dana, 1851 85 Tetralia glaberrima (Hbst.), 1790 The black colouring on the front of Alcock, this iii species 223 p varies in breadth from an almost through bands of greater breadth, to a suffusion of the whole carapace and limbs with dark coloration, and no purpose would be served by keeping Dana's name imperceptible line, But the colouring of the legs will, I think, be found to fall into definite varieties The walking legs, in short, may be either: (1) Uniformly yellow (2) Uniformly dark brown (4) Yellow with a sharp (3) Yellow banded with dark brown across the middle of each joint black spot at the end of the meropodites and propodites (5) Yellow with narrow brown nigrifrons longitudinal An strijjes examination of a long Taken on reefs and in sei-ies lagoons of specimens would jjrobably give interesting results down to 35 fathoms in Goifurfehendu, Fadifolu, Male, Felidu, and Minikoi Atolls 34—2 266 BORRADAILE A L Genus Quadrella Dana, 1851 Quadrella coronata Dana, 1852 86 Var granulosa See Alcock, n iii new All the specimens of Quadrella coronata in the collection belong to a differs from the type in the long (2) are of The chelipeds features: The carapace (1) set in short rows athwart the 266 variety, which distinctly broader than is are only about 2i times as long as the carapace tiny granules over with frosted limb (3) The chelipeds On the underside the granules are less regular in arrangement, and, projecting in profile, give hand the following p the inner (lower) edge of the hand an in-egular, fine denticulation (4) The colour in spirit is a uniform pale flesh-colour, purplish in places By it the differs serrate, three first of these features the but bears about ten long thorns The new variety from that variety in the following points (2) The : allied to var is (1) The fore maculosa Ale, but edge of the arm coloration in spirit is is not different following key shows the jDrincipal characters which separate the known varieties of Q coronata: Carapace as long as broad Chelipeds polished Colour in spirit uniform milk-white Chelipeds 2f times the length of the carapace.] I [Fore edge of arm spined Var A, type Dana, 1851 II More Chelipeds Carapace broader than long or less colour A more or spirit uniform pale flesh-colour less frosted over with granules on the body Fore edge of arm spined Colour in [Chelipeds 2^ times the length of the carapace.] Var B, granulosa n B Fore edge of arm serrate or finely denticulate Fore edge of arm serrate i Colour in a network of fine Colour arranged in a pattern Chelipeds 2^ times the length of the carapace lines Var C, reticulata Ale, 1898 Fore edge of arm finely denticulate ii carapace (?) Chelipeds 2f times the length of the Colour in tiny purple dots Var D, maculata Ale, 1898 Var granulosa was taken on a Gorgonacean dredged in 39 fathoms in Suvadiva Atoll and on a red Alcyonarian dredged in 25 ftithoms in the same Atoll, and was dredged in 23 fathoms in Mahlos Atoll 87 Quadrella bispinosa, Diagnosis : " following points: A n sp (Fig 58.) Quadrella which (1) The carapace is is near akin to Q coronata but differs fi'om it in the than long (2) There is a spine on distinctly broader the anterolateral edge of the carapace, rather farther from the spine at the outer angle of 267 MARINE CRUSTACEANS than from that which marks the junction of the antero- and postero-lateral edges, spine (3) The upper, inner angle of the orbit is not the orbit and rather smaller than the latter spiniform, but is somewhat raised teeth which edge both The minute the upper and lower rims of the orbit are, on this angle, increased in and size farther apart, so set them can just that one or two of be seen (4) The with with naked the granules tiny of varieties granules as is in coronata Q somewhat are underneath the hand arm eye chelipeds are frosted over some The larger The (.5) rather shorter than in Q (6) There are few thorns on the end-joints of the legs, but coronata The these joints are very hairy (7) colour in spirit is a rich orange- brown, paler on the walking legs and fingers A dredged with female in was eggs 25 fathoms in Fig 58 Addu Quadrella hispiiwsa; a whole animal, b part of outside of hand c end of walking leg enlarged enlarged to show the scales, Atoll Subfamily Oziinae It is somewhat remarkable that the collection contains no example of this subfamily, whose genera {Ozius, Epixanthus, Euruppellia and Baptozius) contain several very common species which have been recorded from surrounding localities such as India, Ceylon, the Red and Ortmann {Zool Jahvh Syst Vil.) occasionally report species from the Maldives or Laccadives, but neither of them mentions a Sea, and the Seychelles member Both Alcock (foe cit.) of the Oziinae from those islands Genera incertae sedis Genus Gaecopilumnus, Among like n the decapods taken on the reef at Naifaro in Fadifolu Atoll is a small, Pilumnus- crab whose orbital region has undergone a remarkable transformation, so that the animal appears to be absolutely blind becoming very small, the eyestalks, while the orbit, so orbit should that almost on In a few words, this transformation consists in the orbits the underside of the carapace, and completely filled by the small cornea the outline the of on the underside of the stalk and is hidden in body is quite unbroken over the area where the open lies lie I propose to establish for this with the following characters: (1) crab a new genus, under the name of Gaecopilumnus, Carapace roughly square, convex both fore and aft and from 268 A L side to side, hairy, and grooved above and granular Front-orbital BORRADAILE Front narrow, triangular with rounded apex, hollowed (2) breadth small (3) Anterolateral edge in-egularly set with small spines, passing evenly into posterolateral, without orbital angle by pletely filled which the underside Caecopilumnus hirsutus bare, d mass of front ; is smooth and whole animal, a (4) Orbits small, comEyes with relatively large end-joint but small cornea, end The upper side is granular and hairy like the (5) on the underside at the free is carapace, but Fig 59 eyestalks, not closed b its cuticle outside of hand, view to show orbits closed by eyestalks, pigment within stalk The ischiopodite narrow exopodite e hairs have been taken broad basal joints, which not completely broad, squarish fill is c Antennae with rather (6) view of underside with roof of mouth laid underside of eye enlarged, showing small cornea and off the right side of the body the orbital gap and meropodite, the The caqjopodite transparent latter having attached distally to the (7) its Thir-d maxillipeds \vith fore ridges present and distinct, but not reaching the fore edge of the mouth granular, with pointed fingers The As (10) to the habits, nothing its is (9) (8) Endostome Chelipeds equal, Walking legs stout and of moderate length single specimen being a female, nothing in edge rounded, and meropodite it is impossible to describe the characters of the male known, save that the crab was taken on the reef appearance to suggest a parasitic existence except the reduction of Probably the peculiar conformation of the orbits is due to There its is eyes some circumstance which makes it ; MARINE CRUSTACEANS necessary to guard against the entrance of foreign 269 or enemies bodies can be raised, upon occasion, so that the small eyes are exposed, it is Whether the eyestalks impossible to say, but specimen they are certainly so firmly fixed that they cannot be moved without breaking the carapace The specimen is not well enough preserved to allow of statements being made as to the retina, but a small mass of pigment can be seen through the transparent in the spirit underside of the eyestalk, at some distance from the cornea The systematic the male to the Menippinae If name Diagnosis: its and all n sp it it may view of the fact that in perhaps more closely related is quite possibly be a Catometope which Miers Mag N H VIII p (.5), doubtfully referred 260 (1881)] (Fig 59) to a groove in the middle, fringed with long hairs, which are also over the orbital region and eyestalks and along the sides orbit very small, without orbital tooth or spine or notches in the rim the carapace of ; point behind and above the outer angle extent on the underside of body; the of the the which thus comes to orbit, granules of carapace the anterolateral edge into small spines, arranged in four irregular sets the regions rather faintly marked of the fitting close fill, carapace, ; the eyestalks large relative ; to ; the the anterolateral edge passing with an even sweep into the posterolateral behind, and in front fading entirely to Caecopilumnus with the carapace moderately convex from side to side, aft, granular and pubescent all over, the front strongly bent downwards, sloping inwards sides found "A fore especially species T integrifrons \^Aiin Caecopilumnus hirsutus, strongly so doubtful, is belong to the Xanthidae, it than to any other subfamily, but Typhlocarcinus under the genus the of Rhizopinae, and especially to the the to allied position not known is lie enlarged away at a to a great along the the hinder edge hollowed the orbits, which they against the thin, non-prominent rims, and thus complete the outline simulating the carapace hidden on the underside of the eyestalk ; in their granulation and hairs ; cornea small and chelipeds equal, granular, pubescent and hairy, these features extending to the fingers, the fingers compressed and grooved, with interlocking teeth on their apposed edges, and sharp, crossing tips especially stout, ; and walking the second and third, which have legs of moderate length, very very long propodites, covered with long hairs but without spines." Length : mm Breadth : mm Colour in spirit white : Genus Maldivia A white Gorgonacean, dredged in eight fathoms of water, in North Male, bore a minute but very interesting symbiotic crab, whose peculiarities justify the setting up of a new genus The of this genus (1) Carapace hexagonal, swollen, a roughened with granulations which pass into spines at the sides, and with indications of the regions (2) Front broad, triangular, widely grooved, bent Hind edge strongly downwards (3) Anterolateral edge toothed, about equal to posterolateral seven-jointed wavy (4) Orbits large, very slanting, not fully closed (5) Abdomen of male for it little following are longer than broad, the characters : hairless, Endostome ridges present, but not very strong (7) Eyes large (8) Antennae with slender the fi-ont, and long flagella (9) Merus of third inaxilliped about as long as broad, without a notch in the fore edge, which is straight (10) Chelipeds stout, Piluvinus-Yike, fingers not hollowed at the tip (11) Walking legs moderately stout (6) basal joints which not touch The genus resembles Pilumnus in the shape of the hands and the endostomial ridges 270 L The form recall the of the spinate the carapace, The Quadrella region A BORRADAILE presence of endostomial ridges and the symbiotic habits and front the side of at the granulated carapace, and again the endostomial ridges, show a certain resemblance described and to Caecopilunmus above, though the eyes orbits are very different The form of the antennae points to true position being among its the Me- nippinae, perhaps in the neighbour- hood of Pilumnus Maldivia symbiotica, n sp (Fig 60) A Maldivia whose roughened with small tubercles, which in places, as on Diagnosis carapace the : " is anterolateral lobes, edge, pass into the latter edge with four spines; including the orbital lobe, Fig 60 Maldivia symhiotica, found on a gorgonian, whole animal greatly enlarged each lobe bearing several spines, of which one is larger than the rest, while the lobes decrease in size from behind forwards; the chelipeds equal, bearing on the outside spines set in rows, a row along the upper edge being specially long, the fingers shorter than the hand; the walking legs moderately stout, bearing some long hairs." Length : 1-5 mm Breadth : IQ mm Colour in spirit white : Family Atelecyclidae Subfamily Thiinae Genus Kraussia Dana, 1852 Kraussia rugulosa (Krauss), 1843 Kraussia rugulosa, Dana, U.S Expl Expd Crust, Taken on the Kraussia integra (de Haan), 1837 A reef in Male, Goifurfehendu small specimen p 302, and Minikoi Alcock, from Mahlos Atoll shows I v p pi 19, fig (1852) Atolls 97 characters which recall K nitida Stimps., 1858, in that the frontal lobes are subdivided, though not so deeply as in Stimpson's species, and the carajjace is somewhat narrower than in adult specimens of K integra on the dactylopodites of the legs are small Taken on the reef in Male and dredged in 24 fathoms in Mahlos Atoll The teeth MAEINE CRUSTACEANS 271 Family Hapalocarcinidae This interesting are known, sedis, and taken here is Xanthidae It family of symbiotic crabs, of which, in one case, only the females little Caiman has shown as is, is 43 (1900)], quite incertae [TV Linn Soc Zool (2), viii p convenience alone, and not on account of any relationship to the for discussed at length Caiman's paper in For some remarks on the import- ance of these crabs as affording by their holes a foothold for destructive boring organisms in the blocks, coral Mr by paper a see Stanley Gardiner part this in present the of publication Genus Hapalocarcinus Stimps., 1857 Hapalocarcimos marsupialis Stimps., 1857 Galls containing specimens of were crab this Caiman, found loc cit on Pocillopora lagoon at the in Minikoi and on the reef at Hulule, Male Atoll Genus Gryptoclm-us Heller, 1861 Gryptochirus coralliodytes Heller, 1861 Cryptochirus coralliodytes, Heller, S B Ak Wins Wien, XLiii i p 366, Semper, Anirnal Life, London, 1881, pp 217, 221—223; Caiman, (1861); Mr me Stanley Gardiner has kindly given pi loc II cit figs p the following note on this species : 33—39 47 " A block which had a large number of round holes on the surface, up to mm The holes, when traced in, were nearly all found to be occupied by a symbiotic crab [Cryptochirus] In two holes, however, were crabs of the ordinary form The holes varied in depth from 30 mm., the coral itself [Pseudozius, see above, p 241] of Leptoria across, tenuis was broken up — being in the latter position 48 to the surface hole When —some slightly mm Normally the animal would appear thick projected, the block becomes more or less dry, they retreat into the bottom of the holes I found some deserted holes, perhaps due to an accident in breaking the certainly could is are not wander, on account of the small size obvious that the enclosed it to live close with the carapace as a kind of shield closing the [This refers extremely specimens from common the must crab to in outer have up taken its reef from They the are lagoon rare on at but the crabs of the entrances of the holes abode on the it.] Minikoi, but other corals, which coral, the inner hole, not to the funnel round Leptoria coral, It afterwards These commensals never found in are occasionally massive astraeids from the lagoon at Minikoi, but not apparently in branching occurring in corals, fungoids, or perforate corals." 35 ... water the shape of the body' The species are separated by details ridges the gill-chamber, and such as the shape of the front and the hands, the sculpture and areolation of the carapace, and the. .. they are not sand crabs, nor swimming crabs, nor land crabs, but essentially crabs of the reef surface and the coral stocks, though some of them may be found in other positions Their division... smoothness of the bodies of these crabs is due to the same cause as that of other semiparasitic Decapods, such as the mussel-prawns and crabs (Pontonia and above on p 242, and that Pinnotheres), cause