196 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



keel at its left; brownish cliromatophores. Length, 39.7^. In swamps near 

 Neudoi'f, Switzerland. 



Description. — The body is ellipsoidal, widest at the middle and tapering anteriorly, its 

 length 1.15 transdiameters. The epicone and hypocone are subeqnal in length. The epieone 

 is subconieal with broad, blunt apex. Its length is about 0.5 the total length of the body. The 

 hypocone is slightly narrower near the girdle and broader posteriorly than the corresponding 

 parts of the epicone, with truncate or notched antapex. 



The girdle forms a complete circle near the middle of the body, its distance from the apex 

 being 0.5 of the total length of the body. It has a width of 0.1 transdiameter and is deeply 

 impressed with rounded borders. The sulcus extends from the girdle to the antapex. Its left 

 border is guarded by a well deA-eloped list or projecting keel. The transverse flagellum arises 

 at the junction of the girdle and sulcus and the posterior flagellum slightly below. 



The nucleus is not figured by Schilling (1891). The central part of the body is occupied 

 by a few relatively large, disklike, light to dark brown chromatophores. 



DiMEXsioxs. — Length, 39.7m; transdiameter, 34.5^, as given in the text 

 (Schilling. 1891), but the careful measurement of Schilling's drawings (1891, 

 1913) gives a width of 26/^. This size has been used in finding the proportions 

 given in the description above. 



OccuRRExcE. — Figui'ed by Schilling (1891) from fresh- water swamps and 

 ponds near Neudorf , Switzerland. 



CoMPARisoxs. — This species presents a strildng similarity to G. aeruginosum, 

 G. palustrc, and G. viridr in size and proportions. It differs from them, how- 

 ever, in its shortened dorsoventral diameter and in the list on the left border 

 of the sulcus. It belongs to the vsubgenus Gymnodimum and with the small 

 group of fresh-water species in that subgenus, comprising G. hogoriense, G. 

 rofioidntion, G. pahisfye, G. Hherrii)iiiiii, G. viride, and G. aeruginosum. 



Gymnodinium cinctum sp. nov. 



Plate 7, figure 75 ; text figure X, 28 



Diagnosis. — A minute species with ovoidal body, its length 1.18 transdiam- 

 eters; girdle premedian, displaced nearly twice its own width; sulcus short; 

 ellipsoidal yelloAv ochre chromatophores. Length, 25/*. Pacific off La Jolla, 

 California, July. 



Description. — This species has a minute, broadly ovoidal body, rounded at both apices, 

 widest posteriorly, its length 1.18 transdiameters at the widest part. The hypocone greatly 

 exceeds the epicone in size, having a greater width and exceeding it in length by 0.15 of its own 

 length. The epicone is subconieal (about 70°) with rounded, blunt or slightly pointed apex. 

 Its greatest transdiameter is 0.63 transdiameter of the hypocone. It has a length on the left and 

 right sides of 0.34 and 0.53 respectively of the total length of the body. The hypocone is midway 

 between spherical and hemispherical in outline with broad, rounded antapex. 



The girdle is premedian in position, its proximal end meeting the sulcus at a distance from 

 the apex of 0.34 and its distal end 0.53 of the total length of the body. It sweeps around the 

 body in a descending left spiral direction, displaced posteriorly at its distal end nearly twice its 

 own width. The furrow is relatively wide, about 0.13 transdiameter, and deeply impressed with 



