250 ILLINOIS BIOLOGICAL MONOGRAPHS [460 



EXPLANATION OF PLATE 



Figures 312-332; 336-338. Gregarina rigida (Hall) Ellis. 



Figs. 312-316. An association of sporonts in the process of rotation preparatory to 



cyst formation. X 60. 



Fig. 317. The completed cyst. One nucleus is still visible. X 60. 

 Fig. 318. The protomerite has become homogeneous and the walls of the sporonts 



have disappeared. X 60. 



Fig. 319. A cyst with the protoplasm collected into papillae. X 60. 

 Fig. 320. Two gametes from opposite sides of a cyst, which have just united. 



X 740. 



Fig. 321. The union of gametes is becoming firmer and their chromatin is split- 

 ting. X 740. 

 Fig. 322. Further breaking up of the chromatin and liberation of a polar body (?). 



X 740. 

 Fig. 323. Eight karyosomes have been formed and the wall of separation between 



the gametes has disappeared. X 740. 



Fig. 324. The zygote has become ellipsoidal and its wall has developed. X 740. 

 Fig. 325. A cyst with twelve orange discs on its surface. The spores have col- 

 lected in the center. X 60. 

 Fig. 326. Short spore ducts have developed radiating from the center of the cyst 



like spokes of a wheel. X 60. 

 Fig. 327. Enlarged view of a spore duct. X 195. 

 Fig. 328. The spore duct has become inverted and the spores are being extruded. 



The cyst has shrunken greatly. X 195. 



Fig. 329. A cyst with four spore ducts in the process of extruding spores. X 60. 

 Fig. 330. A spore, showing the cilia or spines at the ends by which the spores are 



held together in chains. The cross-markings indicate faint lines of 



separation between developing sporozoites. Enlarged free-hand from 



highest power (X 1760). 



Fig. 33 1 - Spore, showing chromatin collected in five masses. 

 Fig. 332. A well developed spore in the process of exuding falciform sporozoites 



through an apparent pore at one end. Taken from the intestine of 



a grasshopper. 

 Fig. 333- An association of Gregarina nigra Watson, X 60. This figure, at the left 



of the plate, is labelled 336. 



Fig. 334- Another association of G. nigra. X 60. 

 Fig. 335- Protomerite of G. nigra, showing indentation at apex. X 195. 



Sporadic sporonts. 



Fig. 336- Unique association of three sporonts of G. rigida, X 60. 

 Fig. 337. Unique association of G. rigida, the primite with an epimerite. X 60. 

 Fig. 338. Unique association of G. rigida, two satellites forming an association. 



X 60. 



