THE PARASITIC PROTOZOA OF THE RED GROUSE 325 



in a particular host is not restricted to any one species of Arthropod, but that 

 several organisms, differing in genera as well as in species, may become active 

 agents in the dissemination of protozoal parasites. 



Among Spirochsetes known from the blood of various birds may be mentioned 

 Spirochceta gallinarum of fowls, S. anserina of geese, and a Spirochsete cultivated 

 by Topfer from the blood of the owl. 



S. gallinarum is the pathogenic agent of a fatal disease in fowls, and is spread 

 from bird to bird by the tick, Argas persicus. 



S. lagopodis is much too rare, I think, to be a serious cause of disease in Grouse, 

 although leucocytosis was found in a Grouse infected with S. lagopodis, in the blood 

 of which bird many vacuolated mononuclear leucocytes occurred. 



(B) PARASITES FOUND IN THE ALIMENTARY TRACT OF GKOUSE. 



(a) Plagellata. 

 TRICHOMONAS EBERTHI. 



While examining, on the moors, the csecal contents of Grouse more especially 

 for Spirochsetes I have sometimes observed a flagellate Protozoon moving therein. 



The parasite was seen to possess an undulating membrane, the vibrations of 

 which often regulated the parasite's active movements ; at other times flagella were 

 seen anteriorly whose active forward movements dragged the body of the organism 

 onwards. 



The structure of the parasite is complex. The organism closely resembles, both 

 in size and shape, the parasite described recently (1909) by Martin and Robertson 

 from the caeca of the fowl. The flagellate of the fowl, first seen by Eberth in 1862, 

 was named Trypanosoma eberthi by Kent (1881), Spirochceta eberthi by Liihe 

 (1906), while Stein, Leuckart, and Laveran and Mesnil more correctly considered 

 it to be a Trichomonas. The nomenclature of the parasite is discussed at length by 

 Martin and Robertson (1909). These authors describe both Trichomonas and 

 Monocercomonas forms as well as a Trypanosoma, and state that they " have 

 observed some cases of which the most natural explanation would be to regard the 

 A [Trypanosoma'], B [Trichomonas], and C [Monocercomonas^ conditions as stages 

 in one life -cycle"; otherwise the parasites are distinct and there is a mixed 

 infection. 



It seems to me that the flagellate which I have seen in the caeca of Grouse is 



