230 MEMOIRS OF THE UNIVERSITY OF CALIFORNIA 



P. lunula, Ostenfeld and Schmidt (1901), p. 177. 



P. lunula, Schmidt (1901), p. 138. 



P. lunula, Blackmann (1902), pp. 183, 187, fig. 8. 



P. lunula. Entz, Jr. (1902), p. 92; (1905), p. 108; as Gymnodinium lunula (1907), p. 22; 



(1909), p. 261. 

 P. lunula, Lohmann (1902), p. 52; (1908), pp. 168, 325, 326. 

 P. lunula, Ostenfeld and Paulsen (1904\ p. 170. 

 P. lumila, Karsten (1905), p. 33; (1906), pp. 188, 201; (1907), pp. 233-532, tabulated 



references. 

 P. hmula, Pavillard (1905), pp. 46, 101. 

 P. lumda, Apstein (1906), pp. 263-269; (1909), pp. 1-27. 

 Gymnodinium lunula, Dogiel (1906), pp. 1, 2, 4r-20, pi. 1, figs. 1-25 (figure 20 is not of 



the same species as shown in figures 22-25). 

 Pyrocystis lunula, Zacharias (1906), p. 509. 

 P. limiila, Chatton (1907), p. 284. 

 P. lunula, Gough (1907), pp. 190, 192. 



P. lunula, Okamura (1907), p. 135, pi. 5, fig. 32; (1912), p. 5. 

 P. lunula, Wright (1907), p. 4, pi. 1, figs. 3-5. 

 P. lunula, Paulsen (1908), pp. 110, 111, figs. 153-154. 

 Gymnodinhim lunula, Caullery (1910), p. 211. 

 Pyrocystis lunula, Jollos (1910), p. 203. 

 P. lunula, Wille (1910), p. 296. 

 P. lunula, Doflein (1911), p. 524, figs. 467, 468. 

 P. lunula, Mielcke (1911), pp. 328, 338. 



Diplodinium lumila, Klebs (1912), pp. 389, 390, 442, 443, fig. 4. 

 Gymnodinium lunula, Kofoid and Ridgen (1912), p. 336. 

 Pyrocystis lu7iula, Schiller (1912), p. 28. 

 P. lunula. Cavers (1913), pp. 182, 184, figs. 9._,_^^. 

 P. lunula, Poche (1913), pp. 161, 162. 

 Gymnodinium lunula, Pascher (1916), p. 132. 

 Dissodinium lunula, Pascher (1916), p. 131, fig. 3a. 

 Pyrocystis lunula. West (1916), pp. 55, 57, fig. 40. 

 P. lunula, Lebour (1917&), p. 198. 



D1AGXO8IS. — A small species with ellipsoidal body, its leugtli 1.22 transdi- 

 ameters : girdle submedian, displaced twice its own width ; sulcus extending from 

 apex to autapex; color greenish yellow. Crescentic and spherical Pyrocystis 

 stages prevalent. Length, 22/^. Cosmopolitan in neritic marine habitat. 



Description. — The body is broadly ellipsoidal, circular in cross-section, tapering slightly or 

 rounded at the apices, its length 1.22 transdiameters at the widest part. The epicone and 

 hypocone are subequal in size. The epicone is rounded conical in outline with convex sides and 

 rather broad apex. It has a length on the left and right sides of about 0.45 and 0.5 respectively 

 of the total length of the body. The hypocone is usuallj' slightly more hemispherical than the 

 epicone, with broader antapex. 



The girdle is submedian in position, its proximal and distal ends having a distance from the 

 apex of 0.45 and 0.5 respectively of the total length of the body. The furrow has a width of 

 about 0.14 transdiameter and is deeply impressed with overhanging borders. The sulcus extends 

 in a nearly straight line from the apex to the antapex as a wide, deep furrow. The anterior 

 flagellar pore opens at the proximal junction of girdle and sulcus, the posterior pore a slight 

 distance posterior to the distal one. 



