28 
THOMPSON YATES LABORATORIES REPORT 
papillae nor tubercles are evident. The long oesophagus, extending down beyond 
the vaginal orifice, is about 0*75 mm. long, and bears a narrow bulb marked off 
from the intestine by a slight constriction often hidden by the vagina. The gut 
extends along the whole length of the worm, and terminates at the anus on the 
ventral surface just in front of the posterior extremity of the worm. The anal orifice 
is surrounded by five delicate lips giving a rosette appearance. Side view the 
position of the orifice is marked by a slight baying (plate II, figs. 3 and 4). The vulva 
is at a distance of about 0-33 mm. from the head end, and appears to open ventro- 
laterally. The vagina runs, for a short way, directly backwards, makes a coil 
towards the head end, and runs down. The first portion is very thick-walled with 
small lumen ; beyond this the walls get thinner, and the lumen is seen packed with 
stretched-out embryos. The vagina receives the two horns of the uterus, which coil 
and twist round each other, and extend to the posterior end of the worm. Each horn 
has muscular walls at its entrance into the vagina ; the muscular walls get thinner 
and the lumen narrows somewhat in diameter until a kind of neck is reached following 
a distinct bulbous swelling, in the region of which the muscular walls are much 
thicker, forming a sort of ' pylorus.' Beyond this the tube again narrows, the walls 
are very thick, so that only a narrow lumen is apparent. At the junction of this thick- 
-walled tube (oviduct) with the bulbous swelling (uterus), the former projects into 
the cavity of the latter to form a papilla with an opening at its centre. Beyond this 
thick-walled oviduct is the ovary — a long wider thin-walled portion, which further 
on narrows considerably, becoming cord-like, and ends in a terminal bulb, 
immediately in front of which is a small swelling. The length of the ovary is about 
1 -7 mm. — of the oviduct o - 9 mm. The total length from vulva to the end of the 
ovary is about 26mm. 
Mature ova — spherical cells having large rounded nuclei and distinct 
nucleoli — are found in the large dilated proximal portion of the ovary. The 
narrow-lumened oviduct is empty. The cavity of the uterus near its junction with 
the oviduct, and for some distance down contains innumerable spermatozoa surround- 
ing several ova. Beyond this, the uterus contains ova in all stages of development.* 
Length of ovum containing embryo 39 M . 
Breadth „ „ „ 27 M . 
Length of embryo with its sheath 236 /ul. 
Breadth „ „ 5 to 6 
The male is similar to the female in appearance but considerably smaller ; it 
makes two or three spirals. The tail end has its tip curled ventrally. Length of 
worm 3 - 4 to 3*7 mm. ; breadth 0'2 to 0*3 mm. 
r » c 1 — > 2 '3> i 5"7j 5°> 9 8 ' 6 
Lobb s formula — - — ^ — ±— — — J , J • 
— i'9» 3' 8 > 4'6, 1-5 ' 
* A more detailed account of the histology of the reproductive and other systems of these worms will form the subject 
of a subsequent article. 
