20 



from the microgametoblast, (figs. 7a and 7b). Fertilization of the 

 macrogamete and formation of an 



Oocyst — Segmentation nucleus. Sporogony, (figs. 10-13), the 

 breaking up of the oocyst content to form 



Sporoblasts, (fig. 11), which by further division give rise to 



Sporozoites — Migration of the sporozoites. 



Eimeria stiedae — (Better known as Coccidium oviforme). Causes 

 common and very serious disease of rabbits, occurs rarely in man. 



Description — Infests epithelium of bile ducts, as egg-shaped bodies 

 varying considerably in size (the smaller 26-35^ long by 14-20/u, wide; 

 larger ones 40-49M long by 22-28/* wide) ; with smooth, thick shells 

 having a micropylar-like depression at one pole. Granular contents 

 sometimes distributed uniformly or sometimes collected into a 

 spherical mass. Resemble very greatly eggs of certain parasitic 

 flukes and have been so described. In this stage they pass from the 

 liver and intestines to the exterior where, in presence of moisture, 

 their contents segregate into four oval spores which become sur- 

 rounded by a tough «porocyst. Within each sporocyst are formed 

 two sporozoites. (Note that the excellent account of Leuckart, '86, 

 erroneously refers to these spores as developing into a single sporozoite.) 

 Sporocysts taken up with food by rabbits and the released sporozoites 

 by amceboid motion pass into the tissues. Useless to treat diseased 

 animals. Avoid crowding, isolate diseased rabbits, and keep runs 

 dry and clean. 



■ Order HEMOSPORIDIA 



Blood dwelling sporozoa, intracorpuscular or free in the blood- 

 plasma; with or without alternation of hosts. A somewhat hetero- 

 geneous group, pf which we shall consider two representatives. 



Plasmodium praecox^The genus Plasmodium contains the 

 organisms of malarial fever. Three species generally recognized. 

 True alternation of generations, combined with a change of host. 

 The asexual reproduction, or schizogony occurs in the blood of ipan; 

 the sexual sporogony in the alimentary canal of a mosquito. Follow- 

 ing Schaudinn, we shall describe the life cycle best worked out, that 

 of P praecox, the cause of pernicious malaria. See Leuckart-Chun's 

 Chart, 102, and Schaudinn's explanation thereto. Compare the life 

 cycle of Coccidium schubergii, as given above. 



