KOFOID AND SWEZY: UNARMORED DINOPLAGELLATA 269 



Description. — The body is ellipsoidal, widest at the middle and flattened dorsoventrally, its 

 length 1.3 transdiameters at the widest part. The dorsoventral diameter is about 0.7 of the 

 transdiameter. The epieone and hypocone are subeqiial in size with a tendency' towards enlarge- 

 ment of the hypocone. The epieone is broadly rounded at the apex with a length on the left and 

 right sides of about 0.43 and 0.48 respectively of the total length of the body. The hypocone is 

 slightly wider anteriorly than the corresponding part of the epieone. The antapex is broadly 

 rounded or slightly truncate. 



The girdle is submedian in position, its distance from the apex at the proximal and distal 

 ends being 0.43 and 0.48 respectively of the total length of the body. It is displaced posteriorly 

 slightly more than its own width. The furrow is narrow and deeply impressed with overhanging 

 borders. The sulcus begins midway between the girdle and apex and extends posteriorly to the 

 antapex as a narrow, somewhat obscure trough. 



The nucleus is a spheroidal body located in the central part of the epieone. Its axis is about 

 0.33 transdiameter in length. Numerous green, rod-shaped chromatophores are radially arranged 

 through the cytoplasm. 



Dimensions. — Length, 35f* ; transdiameter, 25h- ; diameter of nucleus, 8/*. 



Occurrence. — Figiired by Penard (1891) from Lake Geneva, Switzerland. 

 Its occurrence has also been recorded by Cunha (1913) from Brazil. 



Co^rrARTSoxs. — This species and G. cannatum, G. palufstrc, G. aeruginosum, 

 G. Hhcr)-i))ni)n, and G. utirahile form a groui^ possessing the same general 

 morphological characters, namely, fresh-water forms with numerous chromato- 

 phores of green or yellow ochre color, and differing but little in general size 

 and proportions. Like Cunha 's (1913) record of G. fuscam, his finding of a 

 cool temperate water species which is common in Lake Geneva in the tropical 

 waters of Brazil raises the qtiestion of the specific identity of his organism with 

 G. fuscum. It is possible, however, that this, like a fe-\v other species of dino- 

 flagellates, such as Prorocentrum micans, is truly cosmopolitan in its range. 



It is very close to G. acrnginosuw in size and proportions, but ditfers in 

 having green instead of bluish green chromatophores and in their being rod- 

 shaped in form instead of elliptical disks. 



Gymnodinium vorticella Stein 



Text figure X, 29 



Peridinium vorticella Stein (1878), pp. 73, 78. 



Gymnodinium. vorticella Stein (3878), p. 90; (1883), pi. 3, figs. 1-4. 



G. vorticella, Eyferth (1879), p. 19. 



G. vorticella, Klebs (1883), p. 356; (1912), pp. 391, 429. 



G. vorticella, Pouchet (1883), p. 402. 



G. vorticella, Biitschli (1885), pp. 986, 1017, pi. 51, fig. 7. 



G. vorticella, Schilling (1891ft), pp. 244, 276; (189]i»), pp. 200, 205, 206; (1913), p. 20, 



fig. 19. Based on Stein's (1878) figure. 

 G. vorticella. Dangeard (1892). 

 G. vorticella, Entz (1896), p. 22; (1902), p. 124; (1907), p. 17; (1909), pp. 253, 254; 



(1910), pp. 162, 164. 

 G. vorticella, Ludwig (1898), p. 299. 

 G. vorticella, Mez (1898), p. 216. 



