HOLOTRICHA 



749 



E. echini L. (Fig. 319, a). About 253/z by 125m; California. 



Genus Entodiscus Madsen. Broadly or narrowly lancet-like, with- 

 out narrowed posterior portion; cytostome small on left narrow side, 

 about 2/5 the body length from anterior end; without trichocysts; 

 macro nucleus central, with a micro nucleus; contractile vacuole sub- 

 terminal; swimming movement rapid without interruption. Two 

 species. Morphology (Powers, 1933, 1933a). 



E. indomitus M. (Fig. 319, 6). 80-117/z by 20-23/z; in the intestine 

 of Strongylocentrotus droebachiensis. 



E. borealis (Hentschel) (Fig. 319, c). Oval; cytostome nearer an- 

 terior end; 105-170/1 by 60-115/*; in the gut of Strongylocentrotus 



Fig. 319. a, Entorhipidium echini, X270 (Lynch); b, Entodiscus in- 

 domitus, X380 (Madsen); c, E. borealis, X380 (Powers); d, Biggaria 

 bermudense, X380 (Powers); e, B. echinometris, X380 (Powers); f, Ano- 

 phrys elongata, X390 (Powers); g, A. aglycus, X390 (Powers). 



