418 BIOLOGY OF THE PROTOZOA 



5. Agamete (merozoite). An agamic spore or product of asexual 

 reproduction. 



6. Gamont (sporont). An individual destined to form gametes. 



7. Gamogony (sporogony). The process of reproduction of a 

 gamont into gametes or gametocytes. 



8. Macrogametocyte. The mother-cell of macrogametes. 



9. Microgametocyte. The mother cell of microgametes. 



10. Macrogamete. The quiescent or inactive gamete fertiUzed 

 by a microgamete. 



11. Microgamete. The motile element in fertilization, equivalent 

 to a spermatozoon. 



12. Gametes. The specialized cells destined to meet and fuse in 

 fertilization. 



13. Zygote (copula). The fertilized cell. 



14. Sporocyst. The fertilization membrane or its equivalent 

 with contents. 



15. Metagamogo7iy. The process of zygotic or post-fertilization 

 reproduction. 



16. Sporohlast. A product of the initial reproduction of the 

 zygote (including both capsule and contents). 



17. Sporozoite. A product of the reproduction of the sporoblast. 

 The significance of these terms will be apparent by illustration 



with a concrete example for which we may again use the classical 

 case of the life history of Eimeria (Coccidivm) sclmhergi as worked 

 out by Schaudinn, 1900 (Fig. 178). This is a common intestinal 

 parasite of the familiar centipede Lithobius, infection taking place 

 by feeding on contaminated food. 



Under the action of the digestive fluids in the centipede the sporo- 

 zoites are liberated from their protective capsules (of sporoblast 

 and sporocyst). A sporozoite penetrates an epithelial cell and 

 grows at the expense of the cell into an agamont (Fig. 178, a). 

 When fully grown the nucleus of the parasite divides several times; 

 the protoplasm by multiple division breaks up into small cells 

 about the resulting nuclei the process of nuclear and cytoplasmic 

 division to form these cells being agamogony. The host cell is 

 destroyed and the young cells, known as agametes, are liberated. 

 These agametes make their way by independent gregariform move- 

 ment to other epithelial cells which they penetrate and in which they 

 repeat the entire agamic cycle, producing in turn, new agametes. 

 After five or six days during which this agamic cycle is repeated 

 resulting in multiple infection of the epithelium, the agametes 

 develop into gamonts or prosexual individuals. Some become 

 large, food-stored cells which, after "maturation" processes form 

 macrogametes directly {e, f, g). Others form large cells with clear 

 protoplasm— microgametocytes— which, after repeated nuclear divi- 

 sions, give rise to a multitude of microgametes, the process being a 



