W. Nicoll 
339 
There is no prepharynx. The moderately lai'ge pharynx has a 
diameter of 004 mm. and it is followed by a somewhat shorter oeso¬ 
phagus. The intestinal diverticula in most specimens are greatly 
dilated and extend almost to the posterior end of the body. 
On each side ol the posterior half of the ventral sucker lies a small 
round testis, with somewhat crenated margin and having a diameter of 
004 mm. Just behind the sucker and slightly to the left side lies the 
globular ovary which is about the same size as the testes. The yolk 
glands are situated to the outer side of the intestinal diverticula, and 
overlapping the latter to a considerable extent. They extend from the 
testes to a short distance behind the level of the ovary. They are very 
compact. The transverse yolk ducts cross behind the ovary. The 
uterus, especially in the less mature specimens, has a characteristic 
cruciform course. It runs backwards from the ovary to the tip of the 
tail, where it makes a turn to one side or the other and then returns. 
When it reaches the level of the yolk glands it makes a single transverse 
convolution across almost the whole breadth of the body and finally 
forms one or two loops just behind the ventral sucker. In more mature 
specimens this arrangement is, to some extent, obliterated. The eggs 
are not numerous and measure 0 03-0 033 x 0 021 mm. Posteriorly they 
are light in colour but in the transverse convolution and in front of it 
they are dark brown, and enclose fully developed miracidia. 
The genital aperture is median, just behind the intestinal bifurcation. 
The cirrus-pouch is small and inconspicuous, and does not reach the 
ventral sucker. 
Genus Mesocoelium Odhner. 
Mesocoelium mieroon n. sp. 
(Plate XXIII, fig. 4.) 
This species was obtained from the duodenum of Hyla coerulea, 
H. gracilenta and Tiliqua scincoides. It is very common and usually 
occurs in numbers of from 10 to 40 in each host. 
It is a moderately small species, measuring 1-2 mm. in length. In 
pressure preparations the length may be as much as 3‘5 mm. No 
specimens under 1 mm. were obtained and one measuring IT mm. was 
fully mature. In three of the larger specimens the average length was 
1‘94 mm. and the greatest breadth, just behind the ventral sucker, 
was 0'77 mm. The outline is elongated oval, pointed at both ends. 
The cuticle is covered with minute closely-set spines which dis¬ 
appear gradually towards the posterior end. The oral sucker, which is 
