140 RESEARCH IN PROTOZOOLOGY 



host, while Kessel (1928a) beHeves that transfer of intestinal 

 protozoa from one species of host to another is more common 

 than is generally supposed. As to the intestinal flagellates of rats, 

 not a great deal has been determined by experiment, so that an 

 inviting field of inquiry is open. 



Since the common rats, especially the Norway rat, have become 

 widely distributed over the earth, they have doubtless carried their 

 flagellates with them, so that these flagellates have an equally wide 

 distribution, but there are many unanswered questions as to the 

 transferability of these flagellates to other animals, including man. 



Tritrichoinonas muris (Galli-Valerio, 1907) has been found by 

 the writer in albino and wild Norway rats, in the wild black rat, 

 in albino and wild gray house mice and in the field mouse (Pero- 

 myscus leucopus). It has been reported from rats and mice in 

 many parts of the world. What appears to be the same species is 

 reported by Becker (1926c) from the ground squirrel (Citellus 

 tridecemlineatus). More studies are needed to determine its host 

 distribution. At present it appears to be limited to rats and mice 

 and the ground squirrel. 



Tritrichomonas minuta Wenrich ( 1924) has been found by the 

 writer in albino and wild Norway rats, in albino and wild gray 

 house mice and in the field mouse (Peromyscus leucopus). It ap- 

 pears to be more common in mice than in rats. Since this species 

 is not generally recognized, its host distribution is unknown except 

 for the statement above. 



Tritrichomonas parva Alexeiefif (1911a), has been found by the 

 writer only in albino and wild Norway rats and it was from a rat 

 that Alexeieff first described it as a new species. Kessel's "T. 

 parva" is probably Pentatriclwmonas. Further studies are necessary 

 to determine its host distribution. 



Pentatrichoinonas has been found by the writer only in albino 

 and wild Norway rats, but is believed to be identical with the 

 species found in man. Kessel (1928/?) transferred what is be- 

 lieved to be this species ("T. parva') from the rat to kittens where 

 it produced definite pathological symptoms. Kofoid and Swezy 

 (1924) state that the Trichomonas of man "may more readily be 

 detected by feeding experiments with flagellate- free rodents than 

 by stool examination in light infections." It is probable that the 

 Trichomonas transferred by Hegner (1928c) from the cecum of 

 the rat to chicks was Pcntatrichomonas. Chatterjee, Harendranath 



