544 PROTOZOOLOGY 



less spiral longitudinal rows; longer cilia at anterior end; cyto- 

 stome near anterior tip; contractile vacuole posterior; in caecum 

 and colon of horse. 



P. colpoidea F. (Fig. 249, a). 70-100^ by 42-60ai. 



P. heckeri Hsiung (Fig. 249, h). 52-98m by 30-52ju. 



Family 12 Isotrichidae Biitschli 



This family includes those forms which possess a thick pellicle 

 and a dense ciliation. 



Genus Isotricha Stein. Ovoid; flattened; dense longitudinal 

 ciliary rows; cytostome at or near anterior end; several con- 

 tractile vacuoles; reniform macronucleus and a micronucleus 

 connected with, and suspended by, fibrils, karyophore; locomo- 

 tion with posterior end directed forward; in stomach of cattle and 

 sheep. 



/. prostoma S. (Fig. 249, c). 80-195m by 53 85^. 



7. intestinalis S. (Fig. 249, d). 97-130iu by 68-88m. 



Genus Dasytricha Schuberg. Oval, flattened; cilia in longitudi- 

 nal spiral rows; no karyophore; in stomach of cattle. 



D. ruminantium S. (Fig. 249, e). 50-75^ by 30-40/^. 



Family 13 Cyathodiniidae da Cunha 



Genus Cyathodinium da Cunha. Conical or pyriform; broad 

 cytostome occupies the entire anterior end and extends pos- 

 teriorly 1/4-3/4 the body length; deep with prominent ridges; 

 oral ciha in a single row on left ridge; body cilia comparatively 

 long, confined to anterior half; macronucleus round or ellipsoid; 

 a micronucleus; 1 to several contractile vacuoles; in caecum and 

 colon of guinea pigs. 



C. conicum da C. Inverted cone; 50-80// by 20-30/x; in caecum 

 of Cavia aperea and C. porcella. 



C. piriforme da C.( Fig. 249,/). Typical form inverted pyriform; 

 second form conical with tapering anterior end; contractile 

 vacuole posterior; 30-40)U by 20~30)u; in caecum of Cavia aperea 

 and C. porcella; Lucas (1932) who made a cytological study of 

 the organism, found some 52 per cent of guinea pigs which she 

 examined in Philadelphia and St. Louis to harbor this ciliate. 



Family 14 Blepharocoridae Hsiung 

 Elongate; cytostome anterior- ventral ; cytopharynx long, cili- 



