Ultrastructure of gamonts and gametes and fertilization of Sarcocystis sp. from the roe deer (capreolus capreolus) in dogs.

Gamonts of Sarcocystis sp. from the roe deer were examined in the intestine of dogs 10 h after inoculation. Early macrogamonts were limited by a three-membranous pellicle, and situated in a parasitophorous vacuole. Female sexual stages during fertilization, the macrogametes, were limited by five membranes, and microgametes were observed in the parasitophorous vacuole. The outer membranes of the microgamete and macrogamete fuse, and the nucleoplasm of the microgamte enters the cytoplasm of the macrogamete. No wall-forming bodies were observed in macrogamonts and macrogametes.