HOLOTRICHA 



625 



since its affinity to other forms is not yet clear. Beers who placed it 

 in Hymenostomata, in agreement with Cheissin states that the nu- 

 trition in two genera is in part saprozoic, and that the organisms are 

 in the process of acquiring the saprozoic habit and the astomatous 

 condition. 



Fig. 294. a, Conchophthirus anodontae, X300 (Kidder); b, C. caryoclada, 

 X200 (Kidder); c. Myxophyllum steenstrupi, X280 (Raabe); d, Hystero- 

 cineta eiseniae, Xl90 (Beers); e, Ptychoslomum bacteriophilum, X375 

 (Miyashita); f, g, dorsal and side views of Ancistruma mytili, X500 

 (Kidder); h, A. isseli, X500 (Kidder). 



Genus Hysterocineta Diesing {Ladopsis Cheissen). Elongate; 

 flattened; flexible, an inverted V- or U-shaped sucker conspicuously 

 present in antero-ventral margin; ciliation uniform; cytostome and 

 cytopharynx at the posterior end; an undulating membrane along 

 peristome which borders the posterior margin of body; macro nucleus 

 elongate; a micronucleus; contracile vacuole posterior; in the intes- 

 tine of gastropods and oligochaetes. 4 species (Beers, 1938). 



H. eiseniae Beers (Fig. 294, d). 190-210^1 by 35-40)li; cytostome 

 not functional; endo plasm with small granules; macro nucleus 45-50/i 

 long; sucker inverted V, about 25-30/i long; in the intestine of Ei- 

 senia lonnhergi. 



