254 PROTOZOOLOGY 



shaped cone; sulcus long; nucleus greatly elongate; salt water. 2 

 species. 



T. rohustum K. and S. (Fig. 108, k). 67-75m long; off California. 



Genus Massartia Conrad. Cylindrical; epicone larger (9-10 times 

 longer and 3 times wider) than hypocone; no sulcus; with or without 

 yellowish discoid chromatophore. 



M. niewportensis C. (Fig. 108, I). 28-37iu long; brackish water. 



Genus Chilodinium Conrad. Ellipsoid; posterior end broadly 

 rounded, anterior end narrowed and drawn out into a digitform 

 process closely adhering to body; sulcus, apex to 1/5 from posterior 

 end; annulus oblique, in anterior 1/3. 



C. cruciatum C. (Fig. 108, m). 40-50iu by 30-40)li; with trichocysts; 

 brackish water. 



Genus Trochodinium Conrad. Somewhat similar to Amphidi- 

 nium; epicone small, button-like; hypocone with 4 longitudinal 

 rounded ridges; stigma; without chromatophores. 



T. prismaticum C. (Fig. 108, n, o). 18-22/i by 9-12/i; epicone 

 5-7ju in diameter; brackish water. 



Genus Ceratodinium Conrad. Cuneiform; asymmetrical, color- 

 less, more or less flattened; annulus complete, oblique; sulcus on half 

 of epicone and full length of hypocone; stigma. 



C. asymmetricum C. (Fig.l08,p). 68-80^ by about lO^t; brackish 

 water. 



Family 6 Blastodiniidae Kofoid and Swezy 



All parasitic in or on plants and animals; in colony forming genera, 

 there occur trophocyte (Chatton) by which organism is attached to 

 host and more or less numerous gonocytes (Chatton). 



Genus Blastodinium Chatton. In the gut of copepods; spindle- 

 shaped, arched, ends attenuated; envelope (not cellulose) often with 

 2 spiral rows of bristles; young forms binucleate; when present, 

 chromatophores in yellowish brown network; swarmers similar to 

 those of Gymnodinium; in salt water. Many species. 



B. spinulosum C. (Fig. 109, a). About 235m by 33-39)li; swarmers 

 5-10^; in Palacalanus parvus, Clausocalanus arcm'corm's and C. 

 furcatus. 



Genus Oodinium Chatton. Spherical or pyriform; with a short 

 stalk; nucleus large; often with yellowish pigment; on Salpa, Anne- 

 lida, Siphonophora, etc. 



0. poucheti (Lemmermann) (Fig. 109, b, c). Fully grown indivi- 

 duals up to 170m long; bright yellow ochre; mature forms become 

 detached and free, dividing into numerous gymnodinium-like 

 swarmers; on the tunicate, Oikopleura dioica. 



