Family Buetschliidae

The characters of this holotrichasin gymnostomorid family have been given above (p. 349).

Genus Alloiozona

The cilia are present in 3 zones - anterior, equatorial and posterior.

Alloiozona trizona Hsiung, 1930 is ovoid, with both ends rounded, and measures 50 to 90 by 30 to 60 u. The cytostome is at the anterior end and is surrounded by a shallow groove provided with short cilia. The cytopharynx is funnel-shaped. The cytopyge is on a knob at the posterior end. The macronucleus is a more or less thick, distinctly granular disc, and is not constant in position. The concretion vacuole is large and is near the surface in the anterior third of the body. There is usually a small, posterior contractile vacuole. Hsiung (1930) found this species in the cecum or colon of 7 out of 46 horses in Iowa.

Genus Ampullacula

The body is flask-shaped. Its posterior half is covered with fine, short cilia, and its neck with longer cilia.

Ampullacula ampulla (Fiorentini, 1890) Hsiung, 1930 measures about 110 by 40 u. The cytostome is at the anterior end. This species occurs in the cecum of the horse.

Genus Blepharoconus

The body is ovoid. The cytostome is small, and the cytopharynx has rods in its wall. There are cilia on the anterior third to half of the body and at the caudal end. The macronucleus is ovoid. There are 3 contractile vacuoles.

Blepharoconus hemiciliatus Gassovsky, 1919 has a conical body and measures 83 to 135 by 45 to 65 u. The macronucleus is nearly spherical. This species occurs in the colon of the horse.

B. cervicalis Hsiung, 1930 is ovoid, with a blunt anterior and a rounded posterior end, and measures 56 to 83 by 48 to 70 u. There is usually a short neck which is formed by a slight groove. The macronucleus is more or less disc-shaped. The concretion vacuole is small and ellipsoidal. Hsiung (1930) found this species in the colon of 2 out of 46 horses in Iowa.

B. benbrooki Hsiung, 1930 is ovoid to ellipsoidal, with a knob-like anterior end and a rounded posterior one, and measures 21 to 37 by 17 to 26 u. The macronucleus is a thick disc. The concretion vacuole is large and ellipsoidal. Hsiung (1930) found this species in the colon or feces of 2 out of 46 horses in Iowa.

Genus Blepharoprosthium

The body is piriform, with a contractile anterior halfo There are cilia on the anterior half and at the posterior end. The macronucleus is kidney-shaped.

Blepharoprosthium pireum Bundle, 1895 measures 54 to 86 by 34 to 52 u. The cytostome is anterior. The cytopharynx is funnel-shaped. The concretion vacuole contains numerous granules and is found in the anterior half of the body close to the surface. There is a contractile vacuole at the posterior end. Hsiung (1930) found this species in the cecum of 13 and the colon of 4 out of 46 horses in Iowa.

Genus Blepharosphaera

The body is spherical or ellipsoidal. Cilia cover the anterior 3/4 of the body, and there is also a caudal tuft of cilia.

Blepharosphaera intestinalis Bundle, 1895 is spherical and 38 to 74 u in diameter. Its macronucleus is a thick, ellipsoidal disc. Hsiung (1930) found this species in the cecum of 9 and the colon of 2 out of 46 horses in Iowa.

B. ellipsoidalis Hsiung, 1930 is ellipsoidal and measures 34 to 65 by 27 to 49 u. Its macronucleus is sausage-shaped. Hsiung (1930) found this species in the cecum of 4 and the colon of 2 out of 46 horses in Iowa.

Genus Blepharozoum

The body is ellipsoidal, with an attenuated anterior end, and is uniformly ciliated. The cytostome is near the anterior tip. There are 2 to 4 contractile vacuoles. The macronucleus is small and kidney-shaped.

Blepharozoum zonatum Gassovsky, 1919 measures 230 to 245 by 115 to 122 u and has an anterior concretion vacuole. It occurs in the cecum of the horse.

Genus Bundleia

The body is ellipsoidal, with a small cytostome. There are cilia at the anterior 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 posterior end, and measures 30 to 56 by 17 to 32 u. The cytopharynx is short and funnel-shaped. The macronucleus is ellipsoidal. The concretion vacuole is small and anterior. There is a small contractile vacuole. Hsiung (1930) found this species in the cecum, colon or feces of 7 out of 46 horses in Iowa.

Genus Didesmis

The anterior end of the body forms a neck behind the large cytostome. 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 u. The cytostome is at the middle of the anterior end, and the cytopharynx is short and funnel-shaped. There is a short neck behind the cytostome. The concretion 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 15 and the colon of 6 out of 46 horses in Iowa.

D. quadrata Fiorentini, 1890 resembles D. ovalis, but has a deep, wide, highly refractive, longitudinal groove on the dorsal surface. It measures 50 to 90 by 33 to 68 u 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 u. 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 Holophryoides

The body is ovoid and uniformly ciliated, with a comparatively large cytostome at the anterior end. The macronucleus is small and ellipsoidal. The contractile vacuole is subterminal.

Holophryoides ovalis (Fiorentini, 1890) Gassovsky, 1919 measures 95 to 140 by 65 to 90 u. There is an accumulation of ectoplasm at the anterior part of the body. Hsiung (1930) did not find this species in Iowa horses.

Genus Paraisotrichopsis

The body is uniformly ciliated and has a spiral groove from the anterior to the posterior end.

Paraisotrichopsis composita Gassovsky, 1919 measures 43 to 56 by 31 to 40 u, and has an elongate macronucleus. Hsiung (1930) did not find it in Iowa horses.

Genus Polymorphella

The body is flask-shaped, with cilia in the anterior region and a few at the caudal end. The macronucleus is discshaped, and the contractile vacuole terminal. The name Polymorphella replaces the original name, Polymorpha, given by Dogiel (1929) because the latter is a homonym of the names previously given to a foraminiferan and a lepidopteran (Corliss, 1960).

Polymorphella ampulla (Dogiel, 1929) Corliss, 1960 measures 22 to 36 by 13 to 21 u. Hsiung (1930) found it in the cecum of 3 and the colon of 1 out of 46 horses in Iowa.

Genus Prorodonopsis

The body is piriform and uniformly ciliated. The macronucleus is sausageshaped. There are 3 contractile vacuoles.

Prorodonopsis coli Gassovsky, 1919 measures 55 to 67 by 38 to 45 u. Hsiung (1930) did not find it in Iowa horses.

Genus Sulcoarcus

The body is ovoid, compressed, with a short spiral groove at the anterior end. The cytostome is at the end of the groove. The cytopyge is terminal. The concretion vacuole is mid-ventral, with the contractile vacuole posterior to it. Cilia are present on the groove, mid-ventral region and posterior end.

Sulcoarcus pellucidulus Hsiung, 1935 measures 33 to 56 by 30 to 40 u. Hsiung (1935) found it in the feces of the mule in China.