388 
S. J. JOHXSTOX. 
walls are thick and muscular. The ovary is three-lobed, the 
lobes being somewhat indistinctly marked off b\" shallow 
grooves. It lies close in front of the right testis, and is 
smaller than that body, being 0'277 mm. in diameter. A small 
shell-gland lies on its left side in the middle line. There is a 
Lanrer’s canal, but no receptacnlnm seminis. 
The coils of the uterus, in closely placed transverse loops 
on the left side, run back to the posterior end of the bod\^ — 
in the worm from which fig. 12 was drawn they do not extend 
so far back as usual — while the ascending loops keep mainly 
to the right of the middle line up to the level of the testes. 
From this point the uterus has a pretty straight course to the 
genital opening ; the vagina is not conspicuously developed. 
The coils of the uterus are entirely confined to the space 
between the intestinal limbs. The yolk-glands consist of 
from six to eight tree-like groups of small follicles on each 
side. The follicles are about 0*017 mm. in diameter, and 
there are 500 or 600 of them in each group. The number of 
groups on each side of the body is sometimes different. Each 
group opens by a separate duct into the longitudinal duct. 
The yolk-glands lie in the lateral field of the body outside the 
intestinal limbs, and extend forwards as far as the anterior 
border of the testes, whilst behind they extend a little beyond 
the middle point between the testes and the posterior end 
of the body. 
The oval eggs are thick-shelled (fig*. 12, a and h) with an 
operculum at the narrow end, while the broad end is often 
provided with a blunt spike. The eggs measure 0*043-0*048 
mm. long by 0*032-0*035 mm. broad, and the shells are 
0*0027 mm. thick. 
A single immature specimen was found amongst the full- 
grown ones. It was 2*58 mm. long by 1*17 mm. broad. The 
suckers and pharynx bore the same relations in size as the 
mature worms. The testes measured 0*179 mm. in diameter; 
the ovary 0*098 mm. There were no eggs, nor could any 
trace of an uterus be made out. 
In addition to the specimens from the gullet of the black 
