HOLOTRICHA 



785 



ciliary rows; macronucleus horseshoe-shape; a large central food 

 vacuole; on solitary or colonial peritrichs such as Vorticella, Zoo- 

 thamnium, etc. (Chatton and Lwoff, 1950). 



Genus Heterocoma Chatton and Lwoff. Body ovoid; ventral side 

 flattened; suctorial tentacle antero-ventral ; 13 ciliary rows make an 

 ellipsoidal field; an adoral zone, five closely-set rows on left and 



Fig. 333. a, Hypocoma parasitica, X1350; b, Heterocoma hyper parasitica, 

 X1200; c, ciliature of Parahypocoma collini, as seen from left-ventral side 

 in life (Chatton and Lwoff). 



seven widely separated rows on right; in the branchial cavity of 

 Salpa (Chatton and Lwoff, 1939). 



H. hyperparasitica C. and L. (Fig. 333, b). Body ovoid, with 

 bluntly pointed posterior end; about 44 p. long; a large food vacuole 

 in cytoplasm ; in the branchial cavity of Salpa mucronata-democratica 

 (Chatton and Lwoff, 1950). 



Genus Parahypocoma Chatton and Lwoff. Ellipsoid; highly flat- 

 tened; anterior end tapers slightly; 29-34 ciliary rows; the adoral 

 zone as in the other two genera; a comparatively short suctorial ten- 

 tacle at anterior end; macronucleus horseshoe-shaped; a large cen- 

 tral food vacuole; parasitic in ascidians. 



P. collini C. and L. (Fig. 333, c). In Ascidia mentula and Ciona 

 intestinalis (Chatton and Lwoff, 1950). 



Family 7 Sphenophryidae Chatton and Lwoff 



Genus Sphenophrya Chatton and Lwoff. Body elongated, "quar- 

 ter orange-" or banana-shaped; attached to the gills of host mollusks 



