THE CILIATES 



365 



The macronucleus is small and kidney- 

 shaped. 



Blepharozoum zonattiDi Gassovsky, 

 1919 measures 230 to 245 by 115 to 122 jll 

 and has an anterior concretion vacuole. 

 It occurs in the cecum of the horse. 



Genus BUNDLEIA 

 Da Cunha and Muniz, 1928 



The body is ellipsoidal, with a small 

 cytostome. There are cilia at the anter- 

 ior and posterior ends, the latter being 

 much less numerous than the former. 



Bundleia postciliata (Bundle, 1895) 

 da Cunha and Muniz, 1928 has a slightly 

 flattened body with a sharply tapering, 

 truncate anterior end and a truncate pos- 

 terior end, and measures 30 to 56 by 17 

 to 32 jM. The cytopharynx is short and 

 funnel-shaped. The macronucleus is el- 

 lipsoidal. The concretion vacuole is 

 small and anterior. There is a small con- 

 tractile vacuole. Hsiung (1930) found this 

 species in the cecum, colon or feces of 7 

 out of 46 horses in Iowa. 



Genus DIDESMIS Fiorentini, 1890 



The anterior end of the body forms a 

 neck behind the large cjdiostome. There 

 are cilia at the anterior and posterior 

 ends. The macronucleus is ellipsoidal. 



Didesmis ovalis Fiorentini, 1890 is 

 oval or rectangular and slightly flattened, 

 with a blunt anterior end and a tapering 

 posterior end. It measures 34 to 55 by 

 27 to 40 /i . The cytostome is at the mid- 

 dle of the anterior end, and the cytopharynx 

 is short and funnel-shaped. There is a 

 short neck behind the cytostome. The con- 

 cretion vacuole is near the anterior end of 

 the irregularly oval macronucleus. There 

 are 1 or 2 contractile vacuoles. Hsiung 

 (1930) found this species in the cecum of 

 16 and the colon of 6 out of 46 horses in 

 Iowa. 



D. quadrata Fiorentini, 1890 resem- 

 bles D. ovalis, but has a deep, wide, 



highly refractive, longitudinal groove on 

 the dorsal surface. It measures 50 to 90 

 by 33 to Q^ii and has a spindle-shaped 

 macronucleus. Hsiung (1930) found this 

 species in the cecum of 8 and the colon of 

 3 out of 46 horses in Iowa. 



D. spiralis Hsiung, 1929 resembles 

 D. quadrata except that it is spirally 

 shaped. It measures 60 to 94 by 38 to 54)i , 

 The dorsal groove runs slightly diagonally 

 to the longitudinal axis. The concretion 

 vacuole contains less than 10 granules. 

 Hsiung (1930) found this species in the 

 cecum of 2 out of 46 horses in Iowa. 



Genus HOIOPHRYOIDES 

 Gassovsky, 1919 



The body is ovoid and uniformly cil- 

 iated, with a comparatively large cyto- 

 stome at the anterior end. The macro- 

 nucleus is small and ellipsoidal. The 

 contractile vacuole is subterminal. 



Holophryoides ovalis (Fiorentini, 

 1890) Gassovsky, 1919 measures 95 to 

 140 by 65 to 90 ji. There is an accumula- 

 tion of ectoplasm at the anterior part of 

 the body. Hsiung (1930) did not find this 

 species in Iowa horses. 



Genus PARAISOTRICHOPSIS 

 Gassovsky, 1919 



The body is uniformly ciliated and 

 has a spiral groove from the anterior to 

 the posterior end. 



Paraisotrichopsis composita Gassov- 

 sky, 1919 measures 43 to 56 by 31 to 40(i, 

 and has an elongate macronucleus. Hsiung 

 (1930) did not find it in Iowa horses. 



Genus POLY MORPHEILA Corliss, 1960 



The body is flask-shaped, with cilia 

 in the anterior region and a few at the 

 caudal end. The macronucleus is disc- 

 shaped, and the contractile vacuole termi- 

 nal. The name Polyrnorphella replaces 

 the original name, Polymorpfm, given by 



