368 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



Cochlodinium geminatum (Hehiitt) Schiitt 

 Text figure HH, 1 



Gymnodinium geminatum Sclivitt (1S95), p. 165, pi. 23, fig. 75. 

 Cochlodinium geminatum, Schiitt (1896), p. 2, fig. 1. 

 C. geminatum, Lemmermann (1899), p. 360. 



DiAGxosis. — Small species, body siibellipsoidal. its length 1.-1—1.67 trans- 

 diameters; girdle a descending left spiral of 1.5-2 turns, displaced about 0.8 

 total length ; sulcus with 0.5-1 turn ; chromatophores vermiculate, ochraceous ; 

 cyst pyriform. Length, il-loH-. Atlantic or Bay of ISTaples; Pacific off La 

 Jolla, California, July. 



Description. — This is based wholly on Schiitt 's (1895, 1896) figures, as the species did not 

 occur at La Jolla in 1917 and our earlier notes are uncritical on its morphology. Serious 

 diificulties are encountered in attempting to work out the morphological features from these 

 figures because aU of them are based on individuals in chain subject to modifications at fission, 

 such as expansion of the conjoined ends, modification in the distinctness of and course of sulcus 

 and girdle, and possible complications of and changes in torsion. Furthermore, there are wide 

 differences between Schiitt 's three figures in size and proportions. These appear to be due to 

 the rounding-up prior to cytolysis, but the differences in size, such as exist between his figures 

 75„ and 75. (75/i and H/j.), when correlated with marked dift'erences in torsion (about 0.5 and 

 1 turn of the sulcus) are at least puzzling and raise the question as to the specific identity of 

 the individuals shown in these two figures. The perplexities are increased when in a later paper 

 (1896) Schiitt reverses the orientation of the cyst of his earlier paper (pi. 23, fig. 75^) and 

 includes in it his figure 75^. On the comparison of Schiitt 's figure lo., with related species the 

 orientation he uses here (1895) appears to be justified, but it hardly seems probable that the 

 chain could turn end for end, as it must do, if his later orientation of the cyst (1896, fig. 1), 

 containing what appears to be the chain of his earlier (1895) figure, is correctly oriented. In 

 short his (1896) orientation of the cyst about the chain in the later figure is irreconcilable with 

 his earlier (1895) figures. A brief attempt to analyze the morphology of this species follows. 



The body is subellipsoidal, wider near the middle, sometimes slightly flattened in the sinistral 

 face and bulging on the dextral: length, 1.40-1.67 transdiameters. Epicone and hypocone sub- 

 equal. Apex asymmetrically subconical (90°), deflected to the right. Antapex also asymmet- 

 rically rounded, subconical to flattened ; deflected to the right. The girdle is a descending left 

 spiral of about 1.5 turns (Schiitt, 1895, pi. 23, fig. 75„), or 2 turns (fig. 703). Its anterior end 

 almost reaches the apex, whence it descends in a fairly uniform spiral to within 0.2 of the total 

 length of the antapex, having a total displacement of nearly 0.8 total length. The furrow is 

 wide, 0.12 transdiameter in width, deeply impressed with overhanging lips. The sulcus is not 

 clearly shown, but appears to run from apex to antapex with a torsion of 0.5-1 turn of a 

 descending left spiral. It is about half the width of the furrow and does not constrict the body. 

 There is no apical loop above the anterior junction with the girdle and the extension beyond 

 the posterior junction is short or lacking. 



The nucleus is central, spherical, or broadly ellipsoidal, 0.5-0.7 transdiameter in diameter 

 or major axis, and crowded with moniliform chromatin threads of uniform granules. The 

 ochraceous chromatophores lie uniformly distributed and about equidistant in the peripheral 

 plasma. They are vermiculate rodlets about 0.2 transdiameter in length and with a diameter 

 0.2 their length. Tliey straighten out and round up into spherules as cytolysis approaches. One 

 or more pusules lie near the anterior flagellar pore. 



