248 ILLINOIS BIOLOGICAL MONOGRAPHS [458 



EXPLANATION OF PLATE 



Figures 290-311. Gregarina rigida (Hall) Ellis. 



Figs. 290, 291. Mature associations, X 195. 



Fig. 292. Trophozoite with epimerite, free in lumen of intestine. X 195. 



Figs. 293, 294, 295, 296. Free trophozoite, with epimerite in process of constriction 

 and destruction. X 195. 



Fig. 297. Longitudinal section of protomerite of satellite, showing indentation for 

 interlocking with primite. X 195. 



Fig. 298. Longitudinal section of protomerite of primite, showing slight indenta- 

 tion in apex and slightly papillate condition sometimes seen. X 195. 



Figs. 299-304. Various appearances of chromatin in the nucleus in sporonts of dif- 

 ferent ages. X 195. 



Fig. 305. View of protomerite of primite showing thickness of sarcocyte and in- 

 dentation at apex. X 195. 



Fig. 306. Myonemes in deutomerite of a nearly transparent individual from a 

 starved host. X 510. 



Fig. 307. Longitudinal striations of deutomerite. X Sio. 



Fig. 308. Cross section of deutomerite through nucleus of a mature sporont show- 

 ing longitudinal striations which appear as cilia, the transparent sar- 

 cocyte, endocyte somewhat mottled in appearance, nucleus slightly 

 shrunken from endocyte in the fixing process, and irregular masses 

 of chromatin, forming the karyosomes. X 195. 



Fig. 309. A young trophozoite attached to an epithelial cell of the host intestine. 



X 195. 



Fig. 310. An association held to a large mass of debris by threads from the poste- 

 rior end of the satellite. Debris has become attached to the threads 

 also. X 30. 



Fig. 311. Enlarged view showing small particles of carmine attached to threads. 

 X 195. 



