kofoide and Campbell 1928 P2

THE DIXOPHYSOIDAE 446 — The species from Amphisolenia quadricauda only the — front of the the antapica! stem branch 5.8 times following respects: differs Description: in in first is longer than the neck and 1.6 the total length of the anterior process and the mid- body; however, this character most striking difference is is probably variable just as in ^ thrinax The that the antapical has four instead of three branches length and of and fourth are subequal and of about the same relative the same shape and structure as the correspondmg branches in A quadricauda The chromatophores Of these the second, third, The proportions of one specimen, the type, Dimensions: — Type specimen of neck, 52 Length midbod}', 44 yu fi Length branch, 245 Length fi and numerous were measured of body, 840 jx Length of head, 10 ix Width of Length of anterior process and midbody, 176 in front of first branch, Length of second branch, 215 of fourth branch, 175 m- /i Length /u 280 fi Length of third branch, Length of antapical stem behind fiigeal protuberance, and right It is therefore dii'ected anteriorly It is fundus its left lip is some- and somewhat to the right The transverse flagellum flagellar pore from the left (tr fl., Kofoid, 1906c, pi Ki, fig 6) arises in the and passes anteriorly between the sulcal lists and encircles the head aromid to the right as in other girdled dmoflagellates SYSTEMATIC ACCOUNT The longitudinal flagellu7n has not been seen by 453 nor us, there any clear is statement in the literature that this flagellum has been seen by any other fig drawing ) pi 12: 3) Hjort (1911, vestigator of the type gives a reproduction of Kofoid's (1906c, However, this addition probably grammatical The posterior displacement of the flagellar pore possible reduction of this flagellum The to- the antapicals, where, as in Ceratium, it is tions apparently structureless When magnifications, however, the wall is or flecked; sometimes it also purely dia- suggestive of a a rudimentary state In most species individuals is is trail- uniform thickness except on the conca^'e faces of thecal ivall is of nearly more robust pi 15, specimen of Triposolenia bicornis to which a long ing flagellum has been added in- these species are examined under high found to be very faintly and minutely spotted is striate cala, are there plainly visible pits somewhat thickened, especially in the it is hyaline and under low magnifica- and In but a smgle species, Triposolenia trunreticulation; this is undoubtedly to be con- more primitive condition Pores are found only in the antapical tubercles and along the sagittal suture on the ventral side of the neck sidered the The sagittal suture is not structurally marked except by a faint Ime, or a few scattered pores along the ventral side of the neck or in the tubercles on the major flexures of the antapicals of each valve The granular The three plates, epithecal, cingular, and hypothecal, have never been found parted in the specimens thus protoplasmic contents (Plate The which nucleus, is 15, fig 2) far observed and coarsely compressed and ellip- are very hyaline located in the midbody, is and has a moniliform chromatin reticulum In the subgenus Ramiciformia, the nucleus and the greater part of the protoplasm are found in the pendent region soidal, of the midbody Near the nucleus canal into the flagellar pore Oiie or flagellar pore, may Lie near it is found a more pusxile, which opens by a slender accessory pusules, also opening into the in the plasma Occasionally the plasma is crowded In with highly refractive ellipsoidal metaplasmic bodies of amyloid character many individuals it is possible to find small irregular, very pale yellowish-green, sometimes nearly colorless chromatophores No species appears to possess the pro- toplasmic structures with a characteristic pattern in either form or distribution The length of the body, measured from the foremost point of the head per- pendicularly to the line connecting the tips of the antapicals (Figure 61), fairly ^'ariable character even within the various species in length for the genus as a whole thus far established — Neither Reproduction: observed as yet Nor fission is is The range 92 /x to 243 sexual reproduction nor binary is a of variation // fission has been there any evidence of a megacytic phase preceding binary THE DINOPHYSOIDAE 454 The entire course of the line of fission probably it is not known with certainty is as follows: — On the dorsal side of the body, along the the head, neck, anterior process, niidbody and antapicals the body, along the middle of the heail, along the of the flagellar pore, crossing the left sulcal list On left side of Most middle of the ventral side of the sulcus, to the just behhid this pore, left and along the middle of the anterior process, midbody, and antapicals This assumption is sup- ported by the conditions in Amphisolenia, as established in the present paper (Plate 13, fig 1-6, 8), and by the following section on the organology The just behind the flagellar pore side of the anterior process with the fisson rib of the left sulcal Near the usually a fine rib, behind \\hich it This rib is, left sulcal list in median it line has no representative of Triposolenia cannot be stated positively that the according to our opinion, homologous other genera of this tribe, iSince tively, Ust swings in toward the continues for a short distance along the ventral Phalacroma, and Dinophysis (Plate anterior which have been indicated in the sagittal plane, just behind the pore, lenia, its facts Plate 13, fig 6; 1, fig e.g., Amphiso- 6; Plate 5, fig 3) has been observed in a stage of division, left sulcal list is and posterior parts are going to the left parted at this and to the rib, it and that right valve respec- but the homologies here indicated make such a division probable In any case, the continuation of the left sulcal runs near the sagittal plane and list behind " the fission rib " in Triposolenia may well belong to the right valve Distribution: — Our present knowledge of the general oceanic distribution of Triposolenia must be regarded as very incomplete by Kofoid The and Jorgensen distributional data avail- (1923), are accompanied by thus can be checked and drawings The genus is marineand probablyexclusivelyeupelagic Wehavefound it to be able, given (1906c, 1907a) extensively distributed throughout the tropical, subtropical, and warm-temperate regions of the Eastern Pacific, of Portugal, and it has been recorded from the southwest coast from the Mediterranean, and from the Marmora Sea by Jorgensen therefore probably of world-wide distribution in tropical, sub- (1923) It is tropical, and warm-temperate waters The except in the regions mentioned above is fact that it has not been found as yet presumably largely due to its very rare occurrence at the surface and the limitation of most plankton collections to surface levels The typical habitat of the genus appears to be the deeper levels of photo- synthesis, predominantly 43) Only one of the eight between 200 and 100 meters (Jorgensen, 1923, known species, Triposolenia bicornis, p 42, has been recorded SYSTEMATIC ACCOUNT as yet from surface waters (Kofoid, 190Gc, p 107) 455 No closing-net data have been published as yet All the species seem to be genus, Triposolenia bicornis rare and Even the most frequent members T ramiciformis, have never been found of the up till the present time except in small numbers The most outstanding peculiarity of the distribution of Triposolenia accord- ing to the data of the Expedition is that the genus did not occur in any of the eighty-one surface catches nor in any of the twenty-four samples of Salpa stom- m surface waters, although achs from specunens taken it is recorded from as many as fifty-nine (46.5%) out of the 127 stations of the Expedition at which Dino- were found flagellates Most of the records are from vertical hauls from 300-0 fathoms, some from vertical hauls from 800, 400, 150, 100-0 fathoms hauls were made at only sixty-eight out of the 127 stations the genus thus were found at no less than 86.8% Vertical Representatives of of the stations at which vertical hauls were made Disregarding the stations at which surface catches only were made, the record stations of Triposolenia are distributed over the area covered by the Expedition in the following mamier (Plate 27): — (100.0%) out of the stations in the California Current (100.0%) out of the stations in the Mexican Current (100.0%) out of the stations in the Panamic Area 16 (76.2%) out of the 21 stations in the Peruvian Current (60.0%) out of the stations in the Easter Island Eddy (100.0%) out of the stations in the Galapagos Eddy 22 (95.7%) out of the 23 stations in the South Eciuatorial Drift (100.0%) out of the station in the South Equatorial Current No vertical collections were made in the Equatorial Counter Current or North Equatorial Current The numbers of these fifty-nine stations are as follows: in the — 4571, 4574, 4580, 4583 (California Current) 4587, 4590, 4594, 4598, 4605 (Mexican Current) 4609, ; ; 4613, 4617, 4634, 4637, 4638 (Panamic 4rea); 4648, 4650, 4652, 4655, 4657, 4659, 4662, 4663, 4665, 4666, 4667, 4668, 4670, 4671, 4675, 4676 (Peruvian Current); 4691, 4697, 4699 (Easter Island Eddy) 4713, 4715 (Galapagos Eddy) 4679, 4681, ; ; 4683, 4685, 4687, 4701, 4705, 4707, 4709, 4711, 4717, 4719, 4721, 4722, 4724, 4728, 4730, 4732, 4734, 4737, 4739, 4740 (South Equatorial Drift) ; 4742 (South Equatorial Current) The fifty-nine stations at which Triposolenia was found (Plate 27) are scat- 00 CM LlJ (- < _l Q < _l _l UJ O < _l Li z Q _I :0 N CL u D UJ PLATE 29 PLATE 29 Distribution of the species of Parahistioneis The explanations of the symbols will be found in the explanation to Plate 24 liJ H < < < _l _l hi O < -I ti z Q J :0 O N Q.' u U) D LjJ PLATE 30 PLATE 30 Distribution of the species of Histioneis The explanations of the symbols will be founfl in the explanation to Plate 24 I- < d < < LU < li z _1 :0 N a.' u D LlJ PLATE 31 PLATE 31 Current chart This chart represents the prevalent ciirrent,s in the ?>Hstern Pacific during the two winter " quarters It is based on the combined data contained in the Quarterly Current Charts for the Ocean" published by the Hydrographic Department, Admiralty, London, and Charts issued quarterly by the Hydrographic Office of the United States Navy Pacific Pilot in the V Miff mmm ^tV', ^ '' w^ ^ H /h % F #.iff ... cingular and sulcal lists and pusules and number, form, and color in the plastic inclusions and Differences in the position, size, and shape of nucleus appear to have little of the chromatophores and. .. Easter Island Eddy, and they have not been found as yet in the Peru^'ian Cur- and rent in the eastern portion of the A schauinslandi (Figure 51), A bifurcata, The differences most tively and probably... current and a remarkably large number is under the direct of records of species in the western and middle portions of the South Equatorial Drift and in the Easter Island Eddy In order to understand