— 214 — 



var. brevis Ostenfeld & Schmidt, Plankton fra det Røde Hav og Aden- 

 bugten, Vidensk. Meddel. Naturh. Foren. Kjøbenhavn, 1901, p. 164, f. 13. 

 10 (rr). 



Area: Red Sea, Indian Ocean. 



var. dispar Pouchet, Contributions à l'histoire des Péridiniens marins, 

 Journ. de l'anat. et de la physiol. 1883, p. 423, fig. D ; non Pouchet in 

 Voyage de „La Manche" à File Jan Mayen et au Spitzberg (Juillet — Août 

 1891), p. 171, fig. 13 B, Paris 1894 = C. mr income (Daday) Cleve. 



A few specimens not differing from Pou chefs figure were met with 

 in two collections. 



2 (rr) - 6 (IT). 

 Area: Mediterranean. 



var. gracilis Schröder, Phytoplankton des Golfes von Neapel, Mitth. 

 a. d. Zool. Stat. zu Neapel, Bd. 14, 1900, Pl. 1, f. 17 b, e; Ostenfeld 

 & Schmidt I.e. p. 164, f. 14; non Gourret, Péridiniens du golfe de 

 Marseille, Annal, du Musée d'hist. nat. de Marseille, zool., vol. I, n° 8, 

 1883, Pl. 1, f. 1. 



2(rr) — 3(rr) — 4(+) -.5(rr) ß(r) - 10 (rr). .! 

 Area: Mediterranean, Red Sea, Indian Ocean. 



5. C. dens Ostenfeld k Schmidt, 1. c, p. 165, f. 16. 



In the main species the left posterior horn is straight or somewhat 

 curved (1. c. fig. 16). In one collection I found a variety of C. dens viz. 



Fig. % Ceratwm dens Ostenfeld & Schmidt, var. reflexa. Ventral view. 



var. reflexa Schm. n. var. (Fig. 2), which is characterized by the 

 direction of the left posterior horn. 



