140 SOME MINUTE ANIMAL PARASITES 



discharge a milky fluid, are found in the liver. 

 Sometimes the fluid becomes practically solid, and 

 a white, chalky mass then can be dug out. When 

 diluted and examined microscopically, it is found to 

 consist of myriads of the cysts of the Eimeria. The 

 mode of transference to other rabbits is by con- 

 tamination of the food-supply by the faecal matter of 

 infected rabbits. Some workers have thought that 

 E. amum and E. stieda are one and the same para- 

 site, but such is not the case. By experiment it has 

 been shown that rabbits fed with food contaminated 

 with E. amum have remained quite healthy, and 

 that the oocysts passed unchanged through their 

 bodies. Similarly, birds given food fouled with ripe 

 cysts of E. stied<z have not become infected. The 

 life-history of the two parasites is similar, but the 

 organisms are distinct, and are in definite relationship 

 with their respective vertebrate hosts. 



The life-histories of all Eimeria are not identical. 

 E. schubergi is found in the common centipede. 

 This parasite has a considerable number of differ- 

 ences from E. amum. It is larger, has more 

 merozoites, which are arranged in a rosette, and 

 has spherical cysts and spores. The method of 

 liberation of the spores also follows a somewhat 

 different course. 



Among the backboned animals a number of 

 marine birds, such as gulls, choughs, kittiwakes, and 

 guillemots are liable to coccidiosis, but an Eimeria 

 is not the cause of their complaint. This is pro- 

 duced by a coccidian belonging to the genus Diplo- 

 spora, which infests the alimentary canal of these 



