666 FAMILY: TRICHOMONADID^ 



in agreement with Kuczynski. The method of formation of the axostyle 

 evidently needs reinvestigation. 



Kofoid and Swezy (1915a) have described a remarkable process of 

 multiple segmentation in T. muris, T. augusta, and other species (Fig. 273). 

 By repeated divisions of the nuclei and blepharoplasts, and formation of 

 new flagella and other structures, complex organisms are produced which 

 may have eight nuclei and sets of organs. By multiple segmentation, 

 eight daughter individuals are formed. These forms were not seen by the 

 writer in a prolonged study of many mice infected with T. ynuris, nor have 

 they been seen by other observers in those species of Trichomonas in 

 which Kofoid and Swezy claim that the process occurs. 



It seems probable that T. muris becomes encysted in spherical 

 cysts about 6 to 8 microns in diameter. These forms were described by 

 the writer (1907). Within the cyst can be seen the nucleus, blepharoplast, 

 axostyle, membrane, and flagella of the flagellate. Kuczynski (1914) 

 states that both in the case of T. muris and T. cavice of the guinea-pig he 

 has seen such encysted forms in which the enclosed flagellates have double 

 sets of organs. It is often difficult to judge whether T. tnuris is encysted 

 or not. The flagellates have a habit of becoming perfectly spherical and 

 quiescent in j^assed faeces, but that such forms are not encysted can be 

 demonstrated by warming them on the warm stage, when they will be 

 seen to renew their activities and assume their usual form. 



Wenrich (1921) believes that two species of Trichomonas occur in 

 mice. The large form, T. tnuris, varies in length from 8 to 20 microns 

 with an average of 12-9 microns. Its nucleus in division has six chromo- 

 somes. The smaller form, which is possibly T. parva of AlexeiefE, varies in 

 length from 6 to 9 microns. During division its nucleus has only three 

 chromosomes. The writer has, however, seen forms which have a length 

 of barely 3 microns. If Wenrich's statement regarding the difference in 

 the chromosome number is accepted, the two species must be recognized, 

 but further information is required before his view is finally adopted. 



Trichomonas caviae Davaine, 1875. — This flagellate, first mentioned and 

 named by Davaine (1875), is very similar to T. muris, and often occurs in 

 large numbers in the caecum and large intestine of guinea-pigs. As already 

 remarked above, it can sometimes be seen to be invading the intestinal 

 wall in sections of the intestine fixed immediately after death. Whether 

 these lesions in which the flagellates occur are caused primarily by the 

 Trichomonas or not has yet to be determined. Like T. muris, with which, 

 indeed, it may be identical, T. cavice varies in length from about 3 to 20 

 microns (Fig. 274). In some infections the csecum is swarming with 

 large forms alone, while in others every transition in size between the 

 smallest and largest individuals can be traced. 



