TRICHOMONAD FLAGELLATES. 341 



(1911a) who found it in the amphibians Salamandra maculosa, Alytes 

 ohstetricans, in the marine teleost Box salpa, and in the leech Haemopis 

 sanguisuga, but notes that it is ahnost certain that the species as thus 

 constituted should be dismembered. 



We have found this species only in the urodele Diemydylus torosus 

 in 80 out of 96 hosts examined between March 19 and December. 

 It was associated with Trichomonas augusta which is usually very 

 abundant, but was as a rule very rare, being found abundantly only in 

 three individuals in March. It was undergoing multiple fission in 

 these hosts but not in the instances of light infection. This restricted 

 and erratic distribution is suggestive of a possible greater abundance 

 in some other host and an accidental or incidental invasion of Diemy- 

 ctylus. In the three hosts with stages of Tetratrichomonas in multiple 

 fission Trichomonas was entirely absent. This fact and the usual 

 small numbers suggest but do not prove an antagonistic relationship 

 between these parasites. 



The Trophozoite. 



This is a small trichomonad, generally somewhat rounded, often 

 pyriform with the larger end posterior, less frequently anterior (PI. 6, 

 Fig. 68). Its length, based on Alexeieff's (1910) figure and excluding 

 fiagella and axostyle, is only 10 /x. In a later (1911d) description 

 he gives the length as 10-14 /x and the diameter as 4-7 /x. In our 

 material it runs somewhat larger, from 12 to nearly 25 n, but geuer- 

 .ally less than 20 /x. 



It has the usual trichomonad organelles, a spheroidal or ellipsoidal 

 nucleus often presenting a diffuse intranuclear chromidial cloud 

 (PI. 6, Fig. 07), with a single (P'ig. 69) or several (Fig. 68) large karyo- 

 somes. An extranuclear chromidial cloud (Fig. 72), and small sparsely 

 present (P'ig. 78) or large densely staining (Fig. 76) cytoplasmic chro- 

 midia arc occasionally seen but they are not regularly present and none 

 has been seen in the axostyle. The nucleus has four chromosomes 

 (Fig. 70). The cytostome (Figs. 67, 68) is relatively large, and food 

 vacuoles, either fluid filled (Fig. 75), or more generally with solid 

 particles (Figs. 67, 70, 77), are found scattered through the cytoplasm. 

 The food taken consists of bacteria (Fig. 77), plant cells (Fig. 67), 

 blood corpuscles of the host, and cysts of amoeba. In one instance an 

 individual (Fig. 69) was found with a large spheroidal cyst described 

 as Blastocystis enierocola by Alexeieff (1911c) enclosed within its sub- 



