ROBERT HEGNER 



663 



with a large sucking disk occupying the ventral anterior region of the body; it has two nuclei, 

 two axostyles, four pairs of flagella, and two parabasal bodies. 



The single human species of the class Coccidia, Isospora hominis (Figs. 9 and 10), is 



9 10 



INTESTINAL COCCIDIUM 



Fig. 9. — Isospora hominis, young oocyst 



Fig. 10. — Isospora hominis, older oocyst containing two spores each with four sporozoites. 

 (From Dobell.)X 1,600. 



INTESTINAL CILIATE 

 Fig. iia. — Balantidium coli, trophozoite. Original 

 Fig. lib. — Cyst of same. (After Dobell and O'Connor.) X 1,000 



