Memoirs MCZ 2605

Itmoirs of tin ^luscum of Comparutibc ^oblogn AT HARVARD COLLEGE Vol XXVI No THE SCIENTIFIC RESULTS OF THE EXPEDITION TO THE TROPICAL PACIFIC, IN CHARGE- OF ALEXANDER AGASSIZ, IN THE U S FISH COMMISSION STEAMER " ALBATROSS," FROM AUGUST, 1899, TO MARCH, 1900, COMMANDER JEFFERSON F MOSER, U S N., COMMANDING IIEPORTS ON VIII THE PELAGIC TUNICATA By WILLIAM E EITTER and EDITH WITH TWO [Published by permission of S Commissioner of CAMBRIDGE, U.S.A.: for BYXBEE I'LATES Geokge M Cowehs, U Prtntcti S tljc iHuscunu August, 1905 Fisli ami Fislieries.] Reports on the Scientific Results of the Expedition to the Tropical Pacific in charge of Alexander Agassiz, by the U S Fish Commis- Steamer sion " Albatross," from August, 1899, to March, 1900, Com- mander JEFFEliSON F MOSER, U COMMANDING S N., VIII THE PELAGIC TUNICATA By WILLIAM E HITTER (Published by permissiou of Geo M Bowers, U The occasion for the present paper that the authors should EDITH ani S Commissioner BYXBEE S of Fish and Fisheries.) was the request of Alexander Agassiz examine the pelagic Tunicates secured by the " Albatross " during her cruise in the tropical Pacific from August, 1899, to The material obtained on March, 1900.^ any teresting of new we take pleasure in is the most in- examined by inscribing to us The Mr Agassiz, is interesting especially The voyage " Albatross " collections yet of the Pyrosoina, which this collections from many upon which report localities in the Pacific is made have been brought together Ocean By far the most important were made b}' the United States Fish Commission steamer "Albatross" on her many voyages since she first entered the waters of the Great Ocean in January, 1888 Cyclosalpa bakeri Ritter Stn A.A., Sept 1, 1899, Lat N 10^ 19', Long 76', surface net, For a list January, 1902 p.m of the Stations Two W 134° 57', surface temp specimens, solitary generation, were taken and a chart of the route see Memoirs M C Z., XXXVI., No 1, EXPEDITION OF THE 196 They were tiie muscle bands, so characteristic of this species, could of the made out dinal glands, ALIJATROSS," 1899-1900 very bad state of preservation, in consequence of which in a arrangement not be " however, the simple hypophysis mouth, and the longitu- ; make the identification reasonably certain- Cyclosalpa afflnis Chamisso Stn 31 A.A., Sept 19, 1899, Lat S 12^ 20', Long temp 80° 144^ 15', surface taken in deepest part of cliannel separating the Marquesas from ; the Paumotu, Long W Two P M 2928, Jan Stn W lis 23, 1889, surface 10', specimens of the solitary generation Southern California, off temp 59° Lat N 32° 47', Six specimens of the aggregate veneration Salpa confoederata scutigera Tliis species seems to be common oif It is rare in the south seas variable Forsk Cuv the coast of California and very It was collected at four stations on these voyages Stn Long 2928, Jan 23, 1889, off Southern California, Lat N 32' 47' 30", W 118' 10', surface 59° temp One specimen the aggregate of generation The test over the posterior part is much thickened and ridged, the ridges covered with papillae Stn 2937, Feb 33° 04' 30", Long 1889, off the coast of Southern California, Lat N 4, W 117° 42', surface temp 62' A number of the aggre- gate generation of various sizes was collected All have the test much thickened over the viscera have short processes scattered over The larger specimens this thickened portion, and a few over the soft anterior part Stn 2946, Feb 6, 1889, off Southern California, Lat N 33° 58', Long 119° 30' 45", surface temp 56.5° The specimens are in A number W of large chains such poor condition that no internal characteristics can be made out, but they seem to belong to this species THE PELAGIC TUNIC ATA 197 W Stn 15 A.A., Sept 8, 1899, Lat N i' 35', Long A 79' young specimen single of the L36' 54', surface temp was collected off the coast of Southern solitary generation on the surface Salpa democratica-mucronata This species was taken at two stations, both Forsk California Stn 2928, Jan temp A 59" 2-3, 1889, Lat N 32^ 47' 30", Long number of W 118 The both generations was collected generation has very long, slender processes at the posterior end these processes are almost as long as the body proach Traustedt's viiv.Jii/gelli/era, but there is In tliis 10', surface solitary In some cases particular they ap- no other resemblance Ijetween the two W Stn 2937, Feb 4, 1889, Lat N 33° 04' 30", Long temp Both generations were 62° 117^ 42', surface collected, exactly similar to those taken at station 2928 Salpa fvisiformis-runcinata Cuv.-CnAM This is the most common Large numbers of species in the collections both generations were taken at different stations from the coast of Alaska South to the Pacific Stn 2869, Sept temp 60° 21, 1888, Lat N 47' 38', Long Between Sitka and the Columbia River W 124' 39', surface Specimens in a very poor state of preservation July 12, 1887-88, Beaver Harbor (no such date given in printed records), There are a number of both generations bearing this British Columbia label The test is somewhat thickened over the posterior part and provided with ridges Stn " Sur 35," 1887-88 Stn " Sur 36," ^3 ^ 1887-88 Mr C H Ti)\viisend writes ns as follows conoevning these station!? "I think surf.ace tow-net No 30 must certain l_v have been made immediately nortli of the (ialapaiios Islands The surface tow-net records of that voyage were not printed in the Albatross report for that year.' ' : station • ' EXPEDITIOISr OF 198 No 1S99-1',)00 would seem that the "Albatross" was it There are a large number Galapagos Islands.^ Stn A.A., Sept A 76' 1, number at the surface, of the aggregate generation 1899, Lat N 18' of 19', Long between 134' surface 57', specimens of the solitary generation were taken P M depth of 150 fathoms and the surface a 6.5 cen in extreme leno-th over the nucleus W 137' 18' to Herdmann by the Two Surface become prismatic them measure of and the smallest measures 4.5 much thickened and is show a tendency tioned by W Four large specimens of the aggregate generation were collected 81" Pacific the vicinity of the in Stn 12 A.A., Sept 4, '99, Lat N 12' 07', Long temp the nearest collection in this cen The test ridged, and the posterior processes Variations of this kind are men- as occurring in large specimens collected in the South " Challenger." Stn 14 A.A., Sept 7, 1899, Lat N 6° 41', Long 82' From record of these two tow-net stations can be found record temp THE "ALBATROSS," One specimen of the solitary were taken on the surface at p and three Two 137°, surface temp of the aggregate generation M All of the aggregate generation have the anterior very short and bifurcated W and posterior processes them have a short process of at the level of the branchial orifice on the left side Stn 15 A.A., Sept temp Two 79° collected 8, 1899, Lat N 4' of the solitary on the surface at All are more or the serrate ridges 35', Long W 136° 54', surface and four of the aggregate generation were p m less angular Those of the aggregate generation have strongly developed, and the test much thickened over the nucleus Stn 31 A.A., Sept 19, 1899, Lat S 12' 20', temp 80' Two Long W 144° 15', surface specimens of the solitary generation were taken on the surface, r m Stn 89 A.A., Oct 14, 1899, Lat S 16' 03.5', temp 80° About one mile N 28° W Long W of north entrance to 145° 43', surface Fakarava Two specimens of the aggregate generation were taken between 350 fathoms and the surface ' See note on page Ut" THE PELAGIC TUNICATA 199 Salpa fusiformis-runcinata form echinata Two specimens uf form were taken on successive days not far from tliis the equator Stn 14 A.A., Sept 82^ One specimen p M It is 7, 1899, Lat N 6' mm in and about 10 mm at the anterior end 137', surface temp was taken at the surface at of the solitary generation cen in length, 15 W Long 41', breadth near the posterior end The chain of blastozooids is well developed Stn 15 A.A., Sept 8, 1899, Lat N 4^ temp 79\ One specimen of the 35', Long W 136' 54', surface solitary generation Salpa cylindrica Cuv Stn N 32° Off the coast of Southern California 2928, Jan 23, 1889 47' 30", Long solitary generation W 118' 10', Stn 2928, Jan 23, 1889 W 118 10', surface temp 59' and only the general shape serves 236 A A., Jan 28, 1900 point of Arhno Lat N A 6° 34', number They of the Gaim to identify About Lat N 32° 47' 30", of specimens apparently are in very bad condition them forty-six miles southwest of south Long E 170' 59', specimens were taken on the surface by electric good condition et Off Southern California belonging to this species were collected Stn number were taken Salpa tilesii-costata Cuv.-Qloy Long A surface temp 59^ Lat surface temp 81° light They Four are in very There are numerous sharp-pointed papillae scattered over the test of the dorsal side Salpa zonariacordiformis Pall-Qcot Specimens Stn of this species were collected at four et Gaim localities A.A., Aug 27, 1899, Lat N 28° 23', Long W 126° 57', surface EXPEDITION OF THE "ALBATROSS," 200 1899-1900 Four specimens of the aggregate generation were temp 66\ collected on the surface at night Three are about One and have rather narrow muscle bands cen in length of these has the posterior extremity prolonged into a about mm in length The fourth specimen prominent process cen long and has is much broader muscle bands than the otlier three W Stn 12 A.A., Sept 4, 1899, Lat N 12" 07', Long temp 81° One specimen One specimen W of the solitary generation W surface collected 136° was taken Stn 31 A.A., Sept 19, 1899, Lat S 12° 20', Long temp 18', end measuring Stn 15 A.A., Sept 8, 1899, Lat N 4° 35', Long 79° was of the aggregate generation 1.5 cen in length,'with a process at the posterior temp 137° It is mm 54', surface at p m 144° 15', surface 80° One specimen of the and four of the others have a solitary generation short bifid process Salpa hexagon a Quoy et This species was collected at three stations Gaim in the tropical Pacific Stn A.A., Sept 2, 1899, Lat N 17° 13', Long yoimg specimen of the solitary generation been down to a depth of 3088 fathoms clusive of the It it The size A 09' in the trawl, cen long, almost exactly twice the his description of the species 136° measures 11 cen two posterior processes which are This makes breadth was taken W single which liad in length, ex- and is cen in given by Traustedt in processes, however, in Traustedt's figures are about } the length of the body and are serrate In this specimen the processes are only ^^ of the length of the body and are smooth In all other respects the specimen agrees perfectly with Traustedt's figures Stn 12 A.A., Sept 4, 1899, Lat N 10° 57', Long temp 81° They W 137° 35', surface Fifteen specimens of solitary generation were collected are all average length young with is cen length of the body a large part of the eleoblast and the processes at tlie still present Their posterior end are ^ of the THE PELAGIC TUNIOATA 201 Long W 137' Sta 12 A.A., Sept 4, 1899, Lat N 10' 54', 35' Fifteen specimens of the aggregate generation were collected on the surface Their ridges are only slightly serrate W Stn 14 A.A., Sept 7, 1899, Lat N 6" 41', Long A 82° single specimen of 137°, surface temp was taken on the the solitary generation surface at p M Pyrosoma giganteum Stn 3474, Hawaiian Dec Islands tively cen long end ; end ; 1891, 6, Surface temp 77 and 21' N Lat cen broad at closed W Long 12', Two Les 157° 38' 30", specimens measuring respec- end and cen broad at open and G cen long and 2.5 cen broad at open end cen broad at closed ; colony narrowing abruptly toward closed end Pyrosoma atlanticum Stn 14 A.A., Sept 7, 1899, Lat N 6' 41', Long 82° Fourteen specimens were talven in the surface W 137°, surface temp tow-net at The M i" largest measures 11.8 cen in length, 2.7 cen in greatest breadth, 2.4 cen at the open, and 1.3 cen at the closed end length, 13 The smallest measures cen greatest breadth, cen at open, and 5.5 cen in at closed end .6 All are of a beautiful clear shining white color Pyrosoma agassizi, Colony cylindrical, External Characters sp nov flaccid, 12 cen long, broad in the middle, tapering very slightly toward both extremities face covered with small quadrangular processes, tapering abruptly from a broad base to an acute point the open end of the colony Common atrial by four large processes of the muscular, quadrangular, tapering to a ))lunt opposite sides of the opening test over to ; opening These processes point; all mm in cen Sur- length, curving toward mm wide, guarded mm long, nonplaced which they curve in Test pairs on between EXPEDITION OF THE "ALBATROSS," 202 processes PL test, I, Test fig mm running down muscles Vessels carrying thin 1899-1900 into thin thick, gelatinous, transparent Zooids visible throu2;h the test, numerous, much flattened laterally, all common opening of the Young by mm broad placed with the dorsal edge toward the mm long among the older larger zooids averaging buds thickly scattered 3Iantle delicate zooids, PI I, and figs colony, the zooids and Muscles of the prebranchial zone well developed, espe- one immediately above the peripharyngeal band cially this Atrial sphincter strong Brcmrhlal test Branchial Aj)pt(ratiis which curves over it, Ventral tentacle present, sac, also about twelve number and meeting on the dorsal side, opening circular slender and zooids of different ages 16 longitudinal Dorsal languets, but the two turning back and forming a broad is Gland conspicuous; large tlie Peripharyngeal band delicate, limbs not angle, within wdiich the dorsal tubercle ; size in these ; Endostyle large, strongly curved about six in number, very slender middle others with usually 20-26 stigmata on each side; bars on each side Gavglion the base of a jirocess of on the side toward the open end of the colony irregularly placed, varying in Branchial orifice at situated its duct long and bent near the Phosphorescent bodies large and prominent in the young zooids, becoming less conspicuous in the older ones, the cells composing them apparently decreasing in number and becoming somewliat scattered Digestive tract stomach near its compact middle Oesophagus short, funnel-shaped, entering the Stomach nearly globular Kectum bent sharply back immediately on leaving the stomach and remaining parallel to PI I, fig it, Atrial chamhcr small Atrial orifice large, circular, furnished single tentacle on its dorsal edge ; this tentacle long, abruptly tapering to an acute point, PI I, fig.s and somewhat with a flattened, Gonads not seen Bads Every large zooid provided with a stolon bearing three buds, the largest of the buds with stolon well developed before it breaks loose THE PELAGIC TUNICATA There is 205 only one specimen of this peculiar form in the collection was taken with the trawl, which had been down 830 fathoms, at Station It 25 A A (in the vicinity of the Marquesas Islands) on Sept 14, 1899, Lat S 8° 48', It Long W 139' 48' seems probable related, it is Bottom temp 38\ Surface temp 80\ that, like a deep-sea form P It sjiinosmn, to which it is most nearly resembles F spinosum in the character of the spines covering the test and possibly in the character of the test though descriptions of also resembles and it in the course in the this structure in this latter species are meagre arrangement of muscles about the branchial taken by the peripharyngeal band itself, It orifice It differs in size, in the possession of an atrial tentacle, and probably in the shape of the zooid and in the character of the digestive tract It will probably appear to students of the pelagic Tunicata that the here species Pyrosoma described is sufficiently distinct from any hitherto known to deserve being regarded as the type of a new genus This was the view held by us until a considerable collection of Pyrosomae recently came into our hands through the kindness of Professor C H Gilbert of the Leland Stanford Junior University, that was secured by the " Albatross on her Hawaiian cruise during the summer of 1902 " In this collection are several specimens identical with the colony here described, excepting that in some of them the four processes about the cloacal orifice are absent We had regarded these as the most important characteristic of the new genus which the it was our intention to establish more conservative course and, form as a highly distinct species We for the of the consequently decided to adopt present at least, treat the new old genus EXPEDITION OF THE "ALBATROSS," 206 Species Ci/chgalpa hfikcri C Date Station A A Sept 2928 29.'37 2946 15 A A S democratica-mucrouatii 2928 2937 J.in Feb 23, '89 4, '89 Sept 21, '88 2869 S fu&lfonnis-ynnclnuta '99 Jan 23, '89 Feb 4, '89 Feb 6, '89 Sept 8, '99 2928 Sdljja conjederata-scut if/era " " Stn.Sur 36 A A 12 A A 14 A A 15 A A 31 A A 13457 76 Surface 20 14415 80 59 Surface S 12 N 32 47 30 11810 S /usi/ormis-nniciniitti form echinatu *S' 89 A A 14 A A 15 A A Sept Sept iiUsii-costata 7, '99 8, '99 Jan 23, '89 2928 S cijlmdrica 23, '89 2928 236 A A Jan Jan 28, 1900 A A A A A A A A Aug 27, '99 A A 12 A A 14 A A Sept Sept Sept 2, '09 12 15 31 S zonariiKorJiformis S hexagona 3474 Pijrosoimi qi(]anl€um Sept 4, '99 Sept 8, '99 Sept 19, "99 N 32 47 30 11810 N 33 04 30 11742 12439 Beaver Harbor N 47 38 1810 134 67 N 12 07 13718 N N 41 35 S 12 20 S 16 03 137 136 54 N 41 N 35 1.37 N 60 70 81 82 79 80 80 136 34 82 79 N 32 47 30 11810 59 11810 59 E 81 N 32 47 J N 34 N 2823 N 12 07 N 35 S 12 20 170 59 126 57 611 13718 f-1 136 54 14415 79 80 Dec N.2112 157 38.30 77 7, '99 N 14 A A Sept Sept 14, '99 S Surface Surface Surface 150 fatlionis to surface Surface Surface Surface 350 fathoms to surface Surface Surface 3088 fathoms C) 82 Surface 41 1.37 82 Surface 848 13948 80 830 fathoiM.s Bottom temp 38° Oikopleura huxleyi (Hixley) is 62 6, '91 '99 7, 25 A A hand 14415 145 43 Surface 59 81 aija&^izt Ritter Appeudicularia flagellum Huxley almost no doubt flagellum described 79 137 35 137 alUinl'iriint is 56.0 136 09 P Tliere 59 62 N 17 13 N 10 57 N 641 4, '99 P Svu 11810 N 32 47 30 N 3304 30 11742 1193045 N 33 58 136 54 N 35 " '87-'88 " '87- '8i Sept 1, '99 Sept 4, '90 Sept 7, '09 Sept 8, '99 Sept 19, '99 Oct 14, '99 Deptli N 10 19 July 12 '87-'88 Stn.Sur.35 Longitude Surface West temp Latitude Sept If), '90 Jan 23, '89 yi A A ajfiitis 1, 1899-1900 by Huxley tliat the species before in 1851, u.s is the Appcndicularia though unfortunately the material at not adequate in either quantity or quality to enable us to reach absolute certainty on the point Length of body of largest specimens mm.+ ; length of tail mm to THE PELAGIC TUNICATA mm.; maximum width 10 1.75 of tail mm 207 Anterior two thirds of body nearly cylindrical, posterior, visceral third considerably larger Tail broadest a short narrowing from here to though scarcely visible distance behind attachment and gradually its long, pointed extremity its Notochord rather thick, through the higlily developed musculature Muscle layer considerably broader on each side of the notochord than the notochord itself, and leaving but a narrow band between of the tail, unoccupied Branchial orifice outer edge and the maro-in by muscle very large, broad, short process on its its elliptical, regular in outline excepting for a ventral side Hyprqjhyseal orgxin large, cone-shaped, the base of the cone directed ventrally and somewhat backward duct, situated on tlie some Extremely long and strong of the cells at the basal end, cilia within the and extending up into apex Ganglion considerably smaller than the hypophyseal organ, and apparently connected with the apical end of the latter Olocjsl, with its contained otolith, rather small and indistinct Peripharyngml band broad, its dorsal limbs reaching far back behind tlie ganglion and hypophyseal organ Endosti/le typically very large ment of the four series of and conspicuous, owing to the great develop- gland cells Oesophagus curved to nearly a semicircle so as to enter the dorsal side of the stomach Stomach large, left lobe much larger than tlie right, the former rounded-quadrilateral in outline as seen from the left side, the antero-ventral angle extended into a broad coecum which reaches of the rectum down along Eight side scarcely developed into a true the left side lobe Intestine arising from the right side, running forward, with a sharp bend toward the median line near its middle, then extendintj; on forward in a nea^rlv straiifht course to terminate close under the posterior end of the endostyle organs, situated on the postero-ventral side of the stomach, small in Sexual all the specimens seen, hence not recognizably composed of male and female elements ; apparently consisting of a single conipact mass The "house," the gill openings anterior end of the endostyle, and the integumcntnrg glands alongside the we have not found, none of the specimens EXPEDITION OF THE "ALBATROSS," 208 being enough preserved, probably, to show the well Furthermore, we :ire different areas of and other a occurs 1899-1900 structures unable to give any definite information about the epithelium oikoplast distinguished Along the dorsal writers band two with epithelium of the side of cuboid distinct, last by Lolimann, 1896, body cells PI II, fig may that 0, be " membranophasts." The absence of the enormous secreting situated on each side of cells the body, well toward the anterior end, and constituting Lohmann the " oval " has surprised us not a to interpret the endostyle, or rather organs the.se little what We were at is called first the great gland cells in it, by inclined as being but microtomic sections of the body revealed at once the ; erroneousness of this conjecture The gland size, cells of the endostyle, and structure of the cell body, the " oval." fig 9, size are apparently quite similar in and form of the nucleus, to those of In none of the species of the genus hitherto described find special reference to the great endostyle, though in some, e.g., development of the gland intermedia, it Lohmann, 1896, they become much like we cells of the appears from the figures of Again, those here described Salensky, 1903, in his recently published detailed anatomical study of vanhoffeni, speaks of the cellules glandulaires." organ as being constituted " de grosses We et hautes are unable, however, to recognize an anterior as distinguished from a posterior part of the organ in any such definite way few cells as is described and figured by Salensky There are, is it true, a at the extreme anterior end, somewhat larger than those of the organ, fig We obvious series ; but that they are different in character or relation siderably clearer than outer ends of the is is not count about twenty of the large cells in each of the four Their nuclei are nearly perfect spheres, regular endostyle rest of the made cells is the It chiefly cell body They in outline, and con- are situated at the extreme should be mentioned that our description of the from specimens examined material not being sufficient to enable us to in toto, sectionized much more than make definitely that the large cells belong to the organ We out not wish to be understood as casting doubt on Salensky's interesting observation relative to the anterior and posterior coeca of the endostyle, both communicating THE PELAGIC TUNICATA witli pharynx through a common small tlie examined in toto 209 We orifice the presence of these coeca mean only not recognizable is that, our in specimens Although Huxley's work on Appendicularia point of view of general morphology, many from the so admirable is upon which the of the details, present-day characterization of species and genera rests, he touched meagrely or not at "House" For example, the glanduhxr areas by which the all Lohmann, he knew noth- secreted, the "oikoplast" epithelia of is In fact his studies on Appendicularia jlagellmn were ing about out his coming in contact with the of the intestinal tract this structui-e very is "house" at made with- Likewise his description all rather too meagre to satisfy the importance that has assumed for purposes of classification at the hands of recent students of the group These deficiencies in Huxley's description and the incompleteness of our own data render the identification of the two forms as one and the same somewhat justified less certain than could be wished ; nevertheless by the following readily recognizable similarities same essentially of the XVIH) attention sjaecies is is and when outline of the 2) of the it branchial of orifice, tlie body (compare two forms is lai'gest species of fig the genus with Huxley's PI essentiall}' the from most other the anterior end to The great or mouth next the tail in this just about equals to be rather sharply differentiated large diameter of This fact will be seen to have special importance nearly three times that of fig are Hux- excepting coplwccrcci, which fig 1, The two inarked " N S." in called to the further fact that the length of The general : believe, and dimensions (compare the measurements size our specimens given above with the size diagram ley's PI we it is, XVHI, same, and would seem species by the relatively accommodate the unusually large lens-th of the forward position of the anus in both forms is rectum and the far another apparentl}' common characteristic Again, the tails agree in being narrowly pointed at the posterior end in both forms, and while this of the other species of the is not an exclusive character, the tails of so many genus are of some other form that considerable weight attaches to this similarity u EXPEDITION OF THE "ALBATROSS," 210 1899-1900 Finally the part of the world from which the two animals come supports the view that they are the same Tliey are both Hu.Kley's specimens were taken tlie Lat 0' to 10' S on coast New Pacific Guinea, situated in and Long 132' to 152° W., while the specimens under conStation 16 A A Lat 2" 38' N., sideration in the present paper are from Long 137' of from the South 22' There are two points only in which the information at hand seems to indicate rather important differences between the "a very figures indicate much more still larger than it that the difference while sac" distinct spherical auditory we have, of course, been attached to the ganglion, and his in our specimens due to the fact that able Huxley says his words that this structure distinctly than seems to be is is two forms to We is assume, however, Huxlev studied livino; animals, examine only preserved ones and rather poorly preserved ones at that The other seeming the notochord as there is is in the musculature of the tail Huxlej-'s As shown present in the specimens examined by us in almost no muscleless zone between the outer border of the muscle and the margin of the of this kind is not indicate as wide a band of muscle on each side of figures certainly fig 1, difference So far as tail, this fact while Huxley's figures show a v/ide zone by itself is concerned, we might suppose the difference to be due again to shrinkage in preservation suffered by our specimens broader It seems, relatively t however, that the nniscle bands the notochord than is our specimens are in Huxley's, and it is not apparent that shrinkage could account for this However, we cannot believe that view of the many strong resemblances this in one apparent difference should have much weight It remains to say a few words concerning the name of our species The name AppeiuHcuIaria New Jlagdlum applied by Huxley, not only to his Guinea specimens, but also to all the Appendicularians subsequently studied by him, he adopted from Chamisso, who had given animal taken by him " near Behring Sea." Mertens in 1831 for an animal discovered by him chamissonis it in 1821 to an Oikopleura was proposed by in the same region, and called Neither Chamisso nor Mertens defined their genera with much accuracy, Chamisso being especially brief and general in his THE PELAGIC TUNICAT A No description was made serious attempt to establish the genera of the group on a secure foundation until Fol published 1872 211 important memoir his in This author satisfied himself of the generic distinctness of the species studied by Chamisso and Mertens, and gave an exact definition of Oilcopleura Fol's treatment of the subject has been accepted There can, by all would seem, be no question, then, that our species it now pleura and not an Appendicularia, as these genera are important and somewhat specific subsequent writers name jlugellum stand Most recent writers Chamisso's description The should the is ? haA'e regarded flageUnm as a nomcn is an Oiko- understood question to be answered difficult is concerned It nudum so far as would be permissible, by the recog- nized rules of nomenclature, for us to take this view of the matter, to then name consider the so to retain it as re-established as Huxley's not Chamisso's objection to this that future research to stand fiar name co recognized and scale may There is, however, the practical discover that the the animal to which Chamisso applied quently thought fitting and adequately defined by Huxley, and it ild wiser to name it name We clear the have have conse- the species anew, and certainly no more be selected than that of the famous zoologist made will place of Appendicularia in the who first zoological BIBLIOGKAPHY Apstein, Garl 1894 Die Thaliacen der Plankton-Expedition B Vertheilung der Salpen Ergebn Brooks, 1893 W d Plankton-Expedition Hutnboldt-Stiftung, Bd II, E d a B K The Genus Salpa Memoirs from tbe Biological Laboratory of the Johns Hopkins University, No II Chamisso, a 1820 De anim Oken, ElSEN, GUSTAF 1874 qiiili Isis, Verm e classe Bd I : De (Lit aiiz.), col Vexillaria speciosa n sp ett Salpa 273-270 Bidrag till Jena Appendiculariornas anatomi Kongl Svenska Vertenskaps-Akademiens Handlingar, Baudet No 12 9, Stock- holm FoL, H 1872 Etudes snr Mem les Appendicnlaires du detroit de Messine tome 21, Geneve Soc Phys Hist nat Geneve, et Bale FoL, Hermann 187G Schleimdriise der Tunicaten Morpholog Jahrb J5d I Herdman, W a 1888 Report on the Tunicata Scientific Results of the Hdxlet, 1851 Voyage of H M S Challenger, Zoology, Vol XXVII T H Observations upon Phil Trans tlie Anatomy and Physiology Roy Soc of London, Huxley, T II 1851 Remarks upon Appendicularia and of Salpa and Pyrosoma pt II, p 207 Dolioluni, two Philosoph Trans, of the Royal Soc of London Genera of the Tunicata for the year 1851, pt II, p 595 LOHMANN, H 1896 III Die Appendicularien der Expedition Zoologische Ergebnisse d v d Gesellsch f Erdkundc z l^icrlin u Leitung Dr Drygalski's ausgesandten Gronlaudexpedition nach Dr Vanhuffeu's bearbeitet Bibliotbeca Zoologica, Hft 20, Lfg 1896 Die Appendicularien der Plankton-Expeilition Ergebnisse der Planktou-Expeditioii der Utnnboldt-Stiftung, Bd v Sammlungcn II E c EXPEDITION OF THE "ALBATROSS," 214 QuoT et 1835 Gaimakd Voyage d decouv dc I'Astrolabe sous Dumont Observ., ElTTER, Wm 1904 d'Urville Jeua Isis, col 850 etc 189'J-1'.)0U E The Pelagic Tiiiiicata of the 8aii Diego Region, excepting the Larvacea 2, No 3, pp 51-112 Univ of California Publications Zoology, Vol Salensky, W 1903 Etudes anatomiques sur les Appendiculaires I Oikopleura vanhoeffeni Loh- manu Mem de L'academie imperiale des sciences de St Petersbourg, phys.-niath Vol Savhjnv, 181(5 XIII, No VHP Sei., Classe J C Memoires sur les Aniuiaux sans Vertebres Seeliger, Ostwai.d 1895 Die Pyrosomen der Plankton-Expedition d Plankton Expedition d Ilumboldl^Stiftung Ergebn Traustedt, M 1885 p Bidrag Bd II E b a til Kunskab om Salperne Vidensk Selsk Skr., Ra-kke, Naturvidng Math Afd Kjobenhavu II II, 8, pp 339-400, Pis Traustedt, M P A 1893 Die Thaliacea der Plankton-Expedition A Systematische Bearbeitung Ergebn d Plankton-Expedition VoGT, Carl Sur 1854 les Mem Tuniciers uageants de de Tlnstit Geuev., t la d Ilumboldt-Stiftung Mer de II, p Nice Bd II E a A I, ABBREVIATIONS A S EXPLANATION OF THE PLATES PLATE Fig Fig J'ljrosoiuu cxjassizi, I shows the open end of the colony, with the four processes around the orifice " " nearly adult zooids, looked at on the posterior side; tlu'ee the side of the atrial orifice, / e., and each with a stolon and two younger zooids Fig " " Fig " '* a single zooid seen from its right side the intestinal tract, with a portion of the branchial sac, and of the posterior end of the eudostyle Fig " '' liie atrial tentacle and the atrial sphincter muscle, with its groups of nuclei PLATE II Fig .5, (irjassizi, the circle of branchial tentacles, showing the larger ventral one Fig " " the ganglion and hypophyseal gland and adjacent structures, Fig " " seen from the inside an enlarged view of one of the groups of nuclei of the Pi/roHoma atrial sphincter muscle Fig Fig 10 ¥\^ 11 Oikoj/lpiira Imxlei/i^ the ' " '• " body of the animal, seen from the right side the intestinal tract and gonad, seen from the ventral side the tail T->nf FmiI Slf/i s \ >4 #"' at: • -T / ^ Putter Byxbee -Tun (lana Suh.CA '''\\\ \\r /I!'" ^ !& fim, '0 Ij I ... 134° 57', surface temp specimens, solitary generation, were taken and a chart of the route see Memoirs M C Z., XXXVI., No 1, EXPEDITION OF THE 196 They were tiie muscle bands, so characteristic... Ergebn Brooks, 1893 W d Plankton-Expedition Hutnboldt-Stiftung, Bd II, E d a B K The Genus Salpa Memoirs from tbe Biological Laboratory of the Johns Hopkins University, No II Chamisso, a 1820 De