INTESTINAL FLAGELLATES OF RATS 141 



and ^litra (1927) have recently described a PcntatricJwmonas 

 {P. canis-auri) from an Indian jackal which may be the same 

 species. The available evidence indicates that this P entatrichomonas 

 has a wide* distribution among mammals and that it is pathogenic 

 to many of them. 



Hexamastix muris Wenrich (1924) has been found by the writer 

 thus far only in the wild black rat (Miis rattits). Further studies 

 will doubtless reveal a wider distribution. Its morphology is very 

 similar to that of the Tetratrichomastix citelli of the ground squir- 

 rel described by Becker (1926c). 



Chilomastix hettencoiirti Fonseca (1915), or what is supposed 

 to be this species, has been found by the writer in albino and wild 

 Norway rats, in the wild black rat, in the house mouse and in 

 the field mouse (Pcromysciis Icucopus). A similar species has been 

 reported for various wild rodents, as, for example, in Gerbillus 

 pygargiis by Chalmers and Pekkola (1918), and in Lateroma 

 (Tatera) lobcngula and Miis concha by Fantham (1925) in Africa. 

 Wenyon (1926) states that he sees no difference between the 

 Chilomastix of man and that of rodents and Kessel (i928fl) says 

 that he has successfully transferred the Chilomastix of man to 

 monkeys and the domestic pig. It will require a great deal of care- 

 fully controlled transfers and a critical study of characters to 

 determine the extent to which the Chilomastix of the rat can 

 colonize itself in other hosts, including man. 



Hexamitiis muris (Grassi, 1882) has been recorded from many 

 different kinds of rats and mice and is apparently widely distrib- 

 uted through this group of rodents. Its possible occurrence out- 

 side this group needs to be investigated. Wenyon (1926) suggests 

 that it may be the same as the fresh water species since it appears 

 in water to which feces containing its cysts have been added. 

 Further studies of this possibility are much to be desired. 



Hexamitiis pulchcr Becker (1926c) was first described from 

 the rat by Prowazek (1904) as Octomitus intcstinalis. The writer 

 has found it in both the albino and wild Norway rat and in both 

 the house mouse and field mouse. It appears to be more common 

 in mice than in rats. Becker (1926c) has described this species 

 from the ground squirrel in Iowa and the writer has found it in 

 a ground squirrel at Flagstaff, Arizona. What appears to be the 

 same species was noted by Alexeieff (1911b) in a salamander and 

 the writer has observed the same organism in various amphibia, 



