66 
Q. H. MARTIN AND MURIEL ROBERTSON. 
5. Trichomonas Gallinarum. 
Trichomonas gallinarum, as will be seen from the 
table, is one of the commonest flagellate parasites of the 
fowl. 
It is rather variable in size (5’4— 7 fi long by 5-6 /i wide). 
Usually the form is more or less spherical, but sometimes the 
longitudinal axis of the body is considerably elongated (cf . 
PI. 11, figs. 11, 12). 
At the anterior end four free flagella arise from a complex 
blepharoplast, and another flagellum, with a similar origin, 
passes down one side of the animal, attached to a fairly well- 
developed membrane, ending freely posteriorly. 
Arising from the blepharoplast, and passing down under 
the membrane is a darkly staining line. This has been termed 
by Dobell in the case of Trichomonas batrachorum the 
“ chromatic base ” of the membrane, but we are inclined to 
regard this structure as homologous with the line found in 
Trichomastix gallinarum, and therefore would prefer to 
use the term “chromatic line.” We return to the very 
important part played in division by this structure in a later 
part of the paper. 
Lying parallel to the line and between it and the base of 
the membrane there are, in the vast majority of cases, a 
number of well-marked blocks, which stain readily with 
chromatic stains. Similar blocks have been found in some, 
species of trypanosomes, Trypanoplas ma, Trichomonas, 
Trichomastix, and Trypanophis. 
Hear the origin of the flagella there is the aperture of a 
short curved pharynx. This is not nearly so well marked in 
this form as in the species which we describe under the name 
of Trichomonas Eber t lii, and can only be seen in favourable 
specimens. 
The nucleus is typically a fairly large oval structure and 
seems to contain a large quantity of closely packed chromatin 
granules, but there is a form of nucleus, the significance of 
