E U CI LI A TA , HOLOTRICHIDA 



369 



Genus Dasytricha Schuberg. Body regularly ovoid. Cyto- 

 stome at the anterior end with a curved cytopharynx. A macro- 

 nucleus and a micronucleus. A single contractile vacuole. 

 One species. 



Dasytricha riiminantium Schuberg (Fig. 159, c). In the 

 rumen of cattle and sheep. 50 to 75 microns long. 



Genus Conchophthirus Stein. Body colorless and not con- 

 tractile. Oval in profile; ventral side less convex. Peristome 

 occurs towards the right side. Cytostome large, in the middle 

 or near the posterior end. Cytopharynx distinct. Usually a few 



Fig. 159 a. Isotricha prostoma. X375 (After Becker and Talbott). 



b. /. intestinalis. X375 (After Becker and Talbott). 



c. Dasytricha ruminantium. X245 (After Becker and Talbott). 



d. Conchophthirus steenstrupii. XlOO (After Quennerstedt). 



e. Buxtonella sulcata. X295 (After Jameson). 



longer cilia at the posterior end. Occasionally adoral zone in the 

 anterior portion of the peristome. Macronucleus spherical, 

 several. Free-living in fresh water or parasitic in the mucous 

 membrane of various molluscs. 



Conchophthirus steenstrupii Quennerstedt (Fig. 159, d). 

 About 175 microns long. 



Genus Buxtonella Jameson. Body oval. A prominent curved 

 ridge runs from one end to the other on the dorsal side, and ex- 

 tends to the ventral side, where a cytostome is located. In the 

 caecum of cattle. 



Buxtonella sulcata Jameson (Fig. 159, e). Body 55 to 124 

 microns long by 40 to 72 microns broad. 



