662 FAMILY: TRICHOMONADIDiE 



to it as CimcB7iomonas muris. As it occurs in mice it was investigated 

 by the writer (1907). It has been recorded from the field vole {Microtus 

 arvalis) by Lavier (19216). T. muris varies in length from 3 to 20 microns. 

 It has the usual pear-shaped body, possesses three anterior flagella, a 

 terminally protruding axostyle, and a well-developed membrane bordered 

 by an axoneme which becomes a flagellum at the posterior end of the 

 organism (Fig. 271). At the base of the flagella is a slit-like cytostome. 

 In stained films the oval nucleus can be seen near the anterior end of the 

 flagellate. It has a definite membrane, and the chromatin is distributed in 

 the form of fine granules throughout its substance, while a central karyo- 

 some may be present. Anterior to the nucleus can be seen two groups of 

 closely aggregated blepharoplasts. The anterior of these gives rise to the 

 three flagella, and the one which borders the undulating membrane. 

 From the other arises a stiff, deeply staining basal fibre, which passes down 

 the body parallel to the base of the undulating membrane. Parallel to 

 the basal fibre, and close to it, is a row of granules, a second row of which 

 may also be present. The axostyle, the pointed tip of which protrudes 

 through the body posteriorly, commences at the blepharoplasts and passes 

 through the body. In the region of the nucleus it seems to pass between 

 the cytostome and the nucleus, and the latter often appears to be partially 

 embedded in it. Wenrich (1921) describes another structure which can 

 sometimes be detected in the cytoplasm, especially after fixation in weak 

 Flemming's solution without acetic acid. It is a sausage-shaped body 

 lying between the nucleus and basal fibre of the undulating membrane 

 (Fig. 271, i). It has a length of a little less than half that of the body. 

 Wenrich considers it to be of the nature of a parabasal. A similar structure 

 was seen by Janicki (1915) in T. hatraclwrum of the frog (Fig. 275), and by 

 Alexeieff (1924) in T. augusta (Fig. 67). 



The cytoplasm contains food vacuoles in which bacteria occur. Occa- 

 sionally, as noted by the writer (1907), large vacuoles filled with bright 

 refractile coccus-like bodies are seen. It was suggested that they were 

 possibly parasitic in nature, and it is now generally recognized that they 

 are spores of a fungus of the genus Sph(srita, which was established by 

 Dangeard (1886) for a similar parasite of free-living amoebae and flagellates 

 (see p. 252). Dangeard recognized the organism as belonging to the 

 Chytridiacese, and gave it the name S. endogena. It was studied in free- 

 living amoebae by Chatton and Brodsky (1909), who gave the name 

 S. dangeardi to a form in Euglena. What may be a distinct species was 

 seen by the writer (1907) in Entamoeba muris and T. muris, by Cragg (1919) 

 in E. coli, by Dobell (1919) in Endolimax nana, and by Noller (1921) in 

 E. coli, E. histolytica, lodamoeba biitschlii, and Dientamosba fragilis. Da 

 Cunha and Muniz ( 1 923) gave the name S. minor to the form in TricJiomonas. 



