376 MEMOIRS OP THE UNIVERSITY OF CALIFORNIA 



CoMPAEisoxs. — This species is a member of the C. miniatuni group of the 

 subgemis CocModinium. It is very near C. convolutum (fig. HH, 5), hut has 

 less torsion, 0.5 instead of 0.6, and less displacement of the girdle, 0.5-0.6 instead 

 of 0.6 total length, and is more ochraceous and less greenish in color. It is 

 larger than C. schuetti (fig. HH, 2) and tajDers more anteriorly. 



Cochlodinium pulchellum Lebour 



Plate 7, figure SO ; text figures HH, 13, 14, 16 



Cochlodinium pulchrllum Lebour 09176), p. 197, fig. 14. 



C. pulchellum, Kofoid and Swezy (1917), pp. 90-91, figs. 3, 4. 



Diagnosis. — A minute species with body symmetrically fusiform, deeply 

 constricted by girdle and sulcus; its length 2.9 transdiameters ; girdle a de- 

 scending left spiral of 3.2 turns, displaced 0.76 total length ; sulcus with torsion 

 of 0.5 turns; color, pale green to glaucous blue. Length, 38/^. Atlantic, Ply- 

 mouth Sound ; Pacific off La Jolla, California, July, August. 



Description. — The body is slender, nearly symmetrically fusiform, widest at the middle, 

 very deeply incised and constricted by the girdle and sulcus, its length 2.9 transdiameters at 

 the widest part near the middle. The body tapers a trifle more posteriorly than anteriorly. 

 The epicone exceeds the hypocone in size, its length being greater by 0.1 total length. It has a 

 hemispherical apex .slightly deflected to the left, and a length at the proximal and distal ends 

 of the girdle of 0.18 and 0.88 respectively of the total length of the body. The hypocone is about 

 half the width of the epicone anteriorly because the sulcus lies nearer the upper than the lower 

 turn of the girdle and follows its course around the body. Below the distal junction of girdle 

 and sulcus it enlarges into the hemispherical antapex, which has no sulcal notch in the post- 

 margin. 



The girdle joins the antapex about 0.18 of the total length of the body from the apex. It 

 sweeps around the body in a descending left spiral of 3.2 turns which steepens from 20° to 30° 

 below the horizontal beyond the first 0.5 turn and joins the sulcus distally about 0.88 of the 

 total length of the body from the apex. Its total intercingular displacement is 0.76 of the total 

 length. It lies in a wide, deep depression with smooth overhanging lips on both sides. The 

 anterior flagellar pore is located at the anterior junction of the girdle and sulcus, the posterior 

 pore slightly beyond the posterior junction. 



The sulcus invades the epicone in a short curved loop directed toward the left of the apex. 

 Below the anterior pore it sweeps down in a gradually steepening descending left spiral of 2.5 

 turns, terminating near the antapex in a small, oblique, antapieal loop which makes 0.5 turn 

 beyond the posterior junction with the girdle. It forms a narrow, deep trough with high, 

 rounded sides. 



The nucleus is spheroidal and median or somewhat postmedian in position. . Its chromatin 

 contents could not be traced. Its diameter is about 0.5 transdiameter in length. 



The cytoplasm is coarsely granular and contains from few to numerous, minute oil droplets 

 and sometimes highly refractive greyish bodies. The color ranges from a light pale cendre 

 green to glaucous blue, diffused throughout the cytoplasm. No striations or other surface 

 markings eould be detected. 



Two individuals were observed within very delicate, transparent cysts slightly larger and 

 conformable to the outline of the body. Both were undergoing binary fission with the nuclei 

 divided in each ease. 



