294 MEMOIRS OF THE UNIVERSITY OP CALIFORNIA 



The girdle begins at a distance from the apex of 0.24 of the total length of the body. It 

 passes around the body in a steep descending left spiral course, becoming displaced 0.67 trans- 

 diameters. The furrow has a width of about 0.08 transdiameter and is deeply impressed. Tlie 

 sulcus is not figured by Pouchet (1885a), but evidently extends at least from the proximal end 

 of the girdle to the antapex. Its borders posteriorly are drawn out into projecting processes, 

 one of which extends slightly beyond the antapex. 



The nucleus and other cytoplasmic inclusions are not figured and no reference is made by 

 Pouchet regarding these structures. The color of the organism, which he notes as similar to that 

 of G. spiralc, is probably greenish. 



Dimensions. — Length, 104/^ ; transdiainetci-, 39^. 



OccuKRENCE. — Figured by Poiieliet (1885a) from collections made in the 

 Atlantic off Concarneau, France, in June. 



Synonymy. — Originally desci'ibed by Ponchet (1885ft) as a distinct species 

 and also as a variety of Gj)mitodininm spiralc. He wavered between these two 

 conceptions in his discussion, introducing both designations in his text and 

 inserting a query ( ?) after his varietal designations in his description of his 

 figure. Lemmermann (1899) transferred it to Spirodimnm as a s^Decies of 

 that genus. 



Gyrodinium crassum (Pouchet) 



Text figure CC, 21 



Gymvodiyiium crassum Pouchet (1885a), pp. 66-67, pi. 4, fig. 28; (1885&), pp. 528, 529, 



pi. 26, fig. 2; (1887), p. 89; (1894), p. 169. 

 G. crassum, Biitschli (1885), pp. 965, 971. 

 G. crassum, Schiitt (1895), p. 40. 

 Spirodinium crassum, Lemmermann (1899), p. 359. 

 S. crassum, Pavillard (1905), pp. 47, 80. 

 S. crassum, Paulsen (1908), p. 103, fig. 141. 

 S. crassum, Lebour (1917&), p. 195, fig. 12. 



Di.\GNOSis. — A large species with long ellipsoidal body, its length 2.54 trans- 

 diameters ; girdle a descending left spiral, displaced 0.92 transdiameter ; sulcus 

 extending from girdle to antapex; surface striate; color, yellowish brown. 

 Length, 165/*. Atlantic, Concarneau, France, in October; Ph^nouth Sound, 

 England, in June ; Arctic Ocean, Gulf of Lyons, October and November. 



Description. — Bod.y elongate ellipsoidal with irregular rounded apices, slightly wider poster- 

 iorly, its length 2.54 transdiameters at the widest part, which is about the middle of the hypocone. 

 The epicone exceeds the hypocone in length by about 0.18 of its own length. It is long, with its 

 sides subparallel to near the apex where they contract irregularly to the narrow, bluntly rounded 

 apex. Its length on the left and right sides is about 0.38 and 0.73 respectively of the total length 

 of the body. The hypocone is slightly wider than the epicone, and is more rounded towards the 

 antapex, the left side of which is notched by the distal end of the sulcus. 



The girdle is posterior to tlie equatorial plane for about 0.75 of its length. It meets the 

 proximal end of tlie sulcus at a distance from the apex of 0.38 of the total length of the body. 

 It sweeps around the body in a descending left spiral, its distal end joining the sulcus 0.73 of 



