910 PROTOZOA AND OTHER ANIMALS 



Treponwnas agilis, the only species that has been described in that 

 genus, is a common flagellate associated with decaying organic matter in 

 fresh water, and has been found in a coprozoic habitat in human feces 

 (Wenyon and Broughton-Alcock, 1924). The writer on several occa- 

 sions found Trepomonas in salt-marsh pools, associated with marine 

 flagellates and ciliates. Whether it was T. agilh was not determined. 

 Flagellates of the genus have also become adapted to an endobiotic 

 habitat in fish, amphibia, and reptiles. Alexeieff (1910) observed Tre- 

 pomotjas in Box sal pa; and Lavier (1936b) found T. ag'dis once in that 

 fish, where, he stated, it is doubtless an accidental saprozoite. According 

 to Alexeieff (1909) and Lavier (1935), the endozoic Trepomonas com- 

 mon in amphibia is probably T. ag'dis. Lavier found the flagellate rather 

 constantly in tadpoles of Rana temporaria, R. esculenta, and Alytes oh- 

 stetr leans, and in one adult Triton. He discussed it as an interesting pos- 

 sibility of parasitism in a flagellate normally living free, and possibly 

 finding the endozoic habitat more favorable than the free-living. Das 

 Gupta (1935) found a species of Trepomonas, usually in small num- 

 bers, in the caeca of three different species of turtles: Terra pene major, 

 Kinosternon hippocrepis, and Chelydra serpentina. A cytological study 

 of the flagellate has recently been made by Bishop ( 1937) . 



The genus Hexamita includes both free-living and endozoic species. 

 The former are common in fresh water and infusions with decaying or- 

 ganic matter; they also occur in salt water; and a species resembling H. 

 in flatus, and only lip long, has been observed by the writer in a salt- 

 marsh pool with decaying algae and a salinity of fifty parts per thou- 

 sand. The type of habitat of the "trichomonad" named Pseudotricho- 

 monas keilini by Bishop (1939) and of Trepomonas and T etramitus is 

 similar to that of Hexamita; Lavier reported them all from one sample 

 taken in France. 



Urophagus and Octomastix are considered by most protozoologists to 

 be synonymous with Hexamita. This was the opinion of Lavier (1936a), 

 who also rejected Octomitus; but he proposed two new genera, Spiro- 

 nucleus and Syndyomita (the latter of which is of the original Octomitus 

 type) for morphological types of Hexamita-Uke flagellates in amphibia. 

 Lavier retained the name Hexamita for the common form in amphibia, 

 the type of which, among those he considers, is most like that of free- 

 living Hexamita. This, H. intestinalis, has undergone little modification. 

 The others differ from the free-living type, according to him; but there 



