Development of the cyst-forming coccidian Sarcocystis muris in the body of its intermediate host

On examining the cyst merogony of S. muris, two patterns of development were established. The one occurs in young cysts where metrocytes underwent endopolygeny, giving rise to the intermediate cells. No dividing metrocytes were seen in the older cysts. Unlike, metrocyte differentiation was observed in these from 1, 2 and 3 step metrocytes to the intermediate cell state, which is the other pattern of development. An original scheme of development within the cysts of S. muris is proposed.