KOFOID AND SWEZY: UNARMORED DINOFLAGELLATA 441 



Pouchetia compacta Schiitt 



Text figures 00, 9, 10 



Pouchetia compacta Seliiitt (1895"), pp. 96, 97 (pi. 27. figs. n7,_-. by citation only). 

 P. contorta Sehiitt (1895), pp. 169, 170, pi. 27, fig. 97^ ,. 

 P. contorta, Lemmermann (1899), p. 360. 



Diagnosis. — A large species; body ver}^ rotund, length 1.1 transdiameters ; 

 girdle a descending left spiral of 1.5 ( ?) turns, disjalaced aliout 0.5 ( ?) trans- 

 diameter; sulcus with about 1.25 turns; ocellus anteroir, sulihorizontal, concen- 

 trated, elongate lens ( f), black, amoeboid melanosome; rosy vacuoles. Length 

 91/^. Plankton Expedition, Atlantic (?), or Bay of Naples. 



Description. — This is ba.secl on Schiitt 's (1895, pi. 27, figs. 97,^-) figures, explanation of 

 figures and brief textual references. Body ver.y rotund (probably much contracted), its longi- 

 tudinal axis only 0.1 greater than its transverse axis. The epicone is broadly rounded, somewhat 

 flattened at the apex, and deeply constricted at the left side. The hypocone.is asymmetrically 

 rounded, the distal end of the sulcus ( 1) deeply notching it on the left side. The sulcus is only, 

 faintly indicated in the second one of Schiitt's figures (text fig. 00, 10), thus making uncertain 

 the definite measurements of regions related to that structure. From these indications the 

 anterior point of junction of the girdle and sulcus would seem to be just above and to the riglit 

 of the ocellus in the body. From that point it passes posteriorly over the notch in the melano- 

 some (text fig. 00, 10) and joins the girdle again distally at a point on the opposite face of the 

 body from that shown in the figure, then sweeps around the hypocone in the deep trough shown 

 in tlie lower part of text figure 00, 9, as the antapical loop. This seems to be the only possible 

 interpretation to be placed on the two figures given by Sehiitt, and the description given here- 

 with is based on that assumption. If this be the true interpretation it makes the epicone consid- 

 erably smaller than the hypocone, with approximate lengths from the apex to the proximal and 

 to the distal extremities of the epicone of about 0.2 and 0.6 of the total length respectively. 



The girdle begins apparently at a point just above the ocellus, passes around the body in a 

 horizontal semicircle before changing its course to a steep spiral in the dorsal side, flattening 

 again prior to its pasterior connection with the sulcus. It thus makes nearly 1.5 turns around 

 tlie body before meeting the girdle distally on the left face of the organism, with a total dis- 

 placement of about 0.5 transdiameter. It forms a broad, rather deep channel throughout its 

 course with the lips smooth and rounded. No pores or flagella have been figured. 



The sulcus takes origin near the apex with an apical loop of about 0.25 turn before its 

 junction with the girdle. It sweeps posteriorly as a deep trough (fig. 00, 10) for 0.5 turn 

 before joining the girdle distally, beyond which it sweeps around the dorsal face of the hypocone 

 as a deep trough for another 0.5 turn, ending close to the left side of tlic aiitape^c. 



The ocellus is situated less than 0.2 of the total length of the botly from tlie apex on the 

 ventral side at the left of the sulcus. Its axis is in part almost horizontal, but the lens is curved 

 posterosinistrally nearly 45°. In Schiitt's first figure (fig. 00, 9), drawn from a fresh, living 

 cell, the ocellus is figured, and described in his explanation of plates, as having a club-shaped, 

 black melanosome with a highly refractive sphere closely connected with it. Several black- 

 pigment masses are present near the border of the girdle and sulcus. In his second figure of 

 the moribund cell (fig. 00, 10) the melanosome is amoeboid and detached pigment masses are 

 more numerous. The lens is apparently disintegrating into spherules, the five rounded bodies 

 close beside the melanosome which lie has designated as lens (/>.«), describing them as highly 

 refractive s])herules with a suri-ouiidiiig wall "Y-oil with pla,stid." The.se are ])Ossibly oil 

 globules, and not the lens diviiled ui) into smaller moieties as he has designated them. The 

 presence of oil globules near the ocellus is a phenomenon of very frequent occurrence through- 

 out the whole genus. On the other hand, the whole evidence throughout the group i)oints toward 



