204 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



There is some question as to the identity of Schiitt 's species and our speci- 

 mens. Our individuals (tig. Y, 6) Avere more rotund than his, and the sidcus 

 extends to the apex, while in his figures it is limited to the h^-pocone. The 

 surface striation is strikingly similar and for this reason we do not separate 

 them. 



Gymnodinium dissimile sp. no v. 



Plate 4, figure 35 ; text figure X, 32 



Diagnosis. — A small species with rotund ellipsoidal hody, its length 1.17 

 transdiameters ; girdle postmedian, displaced half its own width; si;leus ex- 

 tending from apex to antapex ; color grey green. Length, 48m. Pacific off La 

 Jolla. ralifornia, August. 



Description. — The body is rotund, deeply constricted by the girdle, with broad apices, widest 

 anteriorly, its length 1.17 transdiameters at the wide.st part. A cross-sectiou of the body is 

 nearly circular. The epicone greatly exceeds the hypoeone in size, its length being greater by 

 0.46, its transdiameter by 0.07. The epicone is subspherieal, occupying a sector about 210° 

 of a sphere, with broad apex. It has a length on the left and right sides of 0.62 and 0.64 

 respectively of the total length of the body. The hypoeone is constricted anteriorly by the 

 girdle, rounded posteriorly with the antapex deeply notched by the distal end of the sulcus. 



The girdle is situated posterior to the midplane of the body, with a distance from the apex 

 on the left and right sides of 0.62 and 0.64 respectively of the total length of the body. It 

 deeply constricts the body, the transdiameter of the girdle being about 0.8 of the greatest trans- 

 diameter of the body which is in the lower third of the epicone. It extends around the body 

 in a neai-ly transverse direction with a slight posterior displacement on the light of about half 

 its own width. The furrow is wide, about 0.07 transdiameter, and deeply impressed with 

 smoothly rounded sides. 



The sulcus begins a short distance below the girdle and extends posteriorly to the antapex. 

 It is a shallow trough on the epicone, becoming deeper on the hypoeone until near the antapex 

 it reaches the dorsal border of the body, deeply notcliing that part of the hypoeone. The anterior 

 flagellar pore is found at the proximal junction of the girdle and sulcus and the posterior pore 

 midway between that point and the antapex. 



The nucleus is a relatively large, ellipsoidal body in the center of the organism. It is filled 

 with coarse, moniliform, chromatin strands following its long axis. Its major and minor axes 

 are 0.52 and 0.45 transdiameter in length respectively. 



A small sacklike pusule opens into each flagellar pore. The cytoplasm is granular and grey 

 green in color. A few vacuoles filled with a fluid colored like that in the pusules are found in the 

 anterior part of the body. In the peripheral zone are numerous blue-green oil drops and dark, 

 refractive granules. No striae or other surface markings were observed. 



DiiNiExsioxs. — Length, 48^^; transdiameter, 40^; axes of nucleus, 21a' and 18f^. 



OccuRRKxcE. — A single specimen was taken August 3, 1917, 6.5 miles off 

 La Jolla, California, with a No. 000 net, in a haul from 80 meters to the surface 

 and in a siu'face temperature of 21-2 C. 



Co:mp.\eisoxs. — In size, proportion, larger epicone, constricted girdle, and 

 posterior sulcal notch this species is very close to G. contractum sp. nov. (fig. 

 X, 2), but differs from it in having the sulcus extended upon the epicone, in the 

 absence of all striations, and in the absence of the reddish color. 



