SPECIAL MORPHOLOGY AND TAXONOMY OF SPOROZOA 419 



form of gamogony. Each microgamete is provided with two 

 flagella by means of which it moves about in the intestinal fluids 

 until it comes in contact with a macrogamete {h, i, j, s). The 

 gametes fuse, a macrogamete being fertilized by a single micro- 

 gamete (g). The fertilized cell resulting from this fusion is the 

 zygote in which \t he" pronuclei fuse. The fertilization nucleus then 



Fig. 178. — Eimeria schnbergi. Sporozoites penetrate epithelial cells and grow 

 i nto adult intracellular parasites (a). When mature, the nucleus divides repeatedly 

 (b), and each of its subdivisions becomes the nucleus of an agamete (c). These enter 

 new epithelial cells and the cycle is repeated many times. After five or six days of 

 incubation, the agametes develop into gamonts; some are large and stored ■s\-ith yolk 

 material (d, e, /), others have nuclei which fragment into chromidia which become 

 the nuclei of microgametes (d, h, i, j). A macrogamete is fertilized by one micro- 

 gamete (rj) and the zygote forms a sporocyst (fc). This forms four sporoblasts, each 

 with two sporozoites (Z). (After Schaudinn.) 



divides and the two products divide again before the protoplasm 

 divides into four parts, one about each of the nuclei. This process, 

 or metagamogony, results in the formation of four sporoblasts within 

 the sporocyst and each sporoblast has its own indi\idual protective 

 capsule (/). The nucleus of each sporoblast then di\ides and two 

 independent cells are formed in each sporoblast. These inde- 

 pendent cells are the sporozoites. To recapitulate: Sporozoites 



