24 DISEASE-PRODUCING SPOROZOA. 



one or more flagellulse or falciform young, which become con- 

 verted into creatures similar to Euglena (fig. 3, i.), the so-called 

 " Euglenoid phase." These conjugate and encyst, and their 

 contents split up into spores. The reproduction of sporozoa is 

 chiefly by spore formation, the spores being of a peculiar lemon 

 shape in many cases, and are known as " pseudo-navicellsB " (fig. 

 5, m). Each of these spores contains one or more bodies, the 

 falciform bodies, o, each falciform body giving rise to a small 

 flagelloid creature. 



To these Sporozoa are no doubt closely related the curious 

 bodies called Psorosperms found in the liver, muscles, and 

 intestinal slime of animals and man, greatly resembling in 

 appearance pseudo-navicellss. 



The family Gregarinidoe are only parasitic in invertebrate 

 animals, and need no further notice. 



Another family of Sporozoa are called Goccidia, which trans- 

 form themselves into egg-shaped zoosperms by the formation of 

 a capsule and the production of several large spores from their 

 granular contents. 



Disease-producing Sporozoa. — Three well-known maladies are 

 produced in birds, animals, and man by these low forms of life 

 — namely, coccidiosis, or " liver-rot," in the rabbit ; psorosper- 

 mosis of the skin in many animals, and especially birds — the 

 so-called " canker " of pigeons ; and an often fatal malady, 

 diphtheritie roup, in poultry — which the writer has in many 

 instances demonstrated to be due to protozoon parasites of this 

 group. '^ 



Coccidiosis, which we may here take as typical of these 

 diseases, is a common complaint affecting the liver especially of 

 the rabbit, and is produced by the species known as Qoccidium 

 oviforme (fig. , 5). This sporozoon is ovoid when adult, and 

 enclosed in a double-contoured shell from 30/u. to 50/i long and 

 from 20/* to 28/i broad. These extremely minute bodies become 

 encysted, when we observe that their protoplasmic contents 



1 The Parasitic Diseases of Poultry, p. 4. Gumey & Jackson. 1897. 



