— 214 — 
var. brevis Ostenfeld & Schmidt, Plankton fra det Rode Hav og Aden- 
bugten, Vidensk. Meddel. Naturh. Foren. Kjabenhavn, 1901, p. 164, f. 13. 
10 (rr). 
Area: Red Sea, Indian Ocean. 
var. dispar Pouchet, Contributions a l'histoire des Péridiniens marins, 
Journ. de V’anat. et de la physiol. 1883, p. 423, fig,D; non Pouchet in 
Voyage de ,La Manche‘ & I’ile Jan Mayen et au Spitzberg (Juillet-—Aott 
1891), p.171, fig. 13B, Paris 1894 — C. curvicorne (Daday) Cleve. 
A few specimens not differing from Pouchet’s figure were met with 
in two collections. 
2ar) — 6(Qr). 
Area: Mediterranean. 
-var. gracilis Schréder, Phytoplankton des Golfes von Neapel, Mitth. 
a. d. Zool. Stat. zu Neapel, Bd. 14, 1900, Pl. 1, f. 17b,e; Ostenfeld 
& Schmidt lc. p. 164, f.14; non Gourret, Péridiniens du golfe de 
Marseille, Annal. du Musée d’hist. nat. de Marseille, zool., vol. I, n° 8, 
1888, Pl.i, f. 1. 
2@ar) — 3(rr) — 4(+) — 5Qr) — 6) — 10@r). 
Area: Mediterranean, Red Sea, Indian Ocean. 
5. €, dens Ostenfeld & Schmidt, l.c., p. 165, f. 16. 
In the main species the left posterior horn is straight or somewhat 
curved (l.c. fig. 16). In one collection I found a variety of C. dens viz. 
Fig. 2. Ceratium dens Ostenfeld & Schmidt, var. refleaa. Ventral view. 
_ var. reflexa Schm. n. var. (Fig. 2), which is characterized by the 
direction of the left posterior horn. 
