104 RESEARCH IN PROTOZOOLOGY 



connection, however, how much careless work has been done in 

 the line of species differentiation. Even in the most recent litera- 

 ture on the subject Perard (1925) and VVaworuntu (1924) the 

 liver and intestinal types are not clearly differentiated. Recent 

 studies in the writer's laboratory on this subject have led to the 

 differentiation of five species of coccidia in rabbits, all Eiineria, 

 one being a liver type and four being intestinal types. With the ex- 

 ception of one species, the intestinal coccidia may be differentiated 

 from E. sticdce of the liver by the presence of a residual body 

 outside the sporocysts in the ripe oocyst. The fourth intestinal type 

 simulates rather closely the liver type and is differentiated from 

 the same by size and shape of the micropyle. The five species of 

 Eimeria in rabbits recognized in recent studies are : 



E. stiedce Lindemann, 1865, the common liver type. Shows no 

 residual body in ripe oocyst. 



E. magna Perard, 1925, large intestinal type with pronounced 

 lips bounding micropyle. Prominent residual body present. 



E. perforans Leuckart, 1879, small intestinal type without 

 noticeable lips or micropyle. Residual body present. 



E. media sp. novo., smaller than E. magna and without pro- 

 nounced lips bounding micropyle. Residual body present. 



E. irresidua sp. novo., large intestinal form without residual 

 body. Lips bounding micropyle less pronounced than in E. jnagna. 



Host-parasite relationships between the coccidia of rabbits and 

 of other animals, particularly guinea-pigs, rats, and other closely 

 related forms, need to be investigated in greater detail than ob- 

 served heretofore, although studies to date (Andrews, 1927, and 

 Wenyon, 1926) indicate, with the exception of the Isospora of 

 cats and dogs, that the specificity of host-parasite relations among 

 coccidia are quite rigid. 



6. GUINEA-PIG 



The guinea-pig, though a common laboratory animal, harboring 

 many intestinal protozoa, has never been used extensively in ani- 

 mal-transfer experiments. Endama^ba cohaycc, Walker, 1908, a 

 form resembHng E. coll, has been seen by Chatton (1918), Wen- 

 yon (1926), and Holmes (1923). Leger (19 18) and Baetjer and 

 Sellards (1914) and Chatton (1918) have also recorded a tetra- 

 nucleate type. Hegner (1926) names Endolimax cavice from the 

 guinea-pig, and also Giardia cavi<c (1923). Trichomonas cavice 



