1909. ] THREAD-WORMS OF THE RED GROUSE. 339 
one-twenty-fifth of the body-length from the anterior end, be the 
nerve-ring, I saw nothing of the nervous system. 
The ovaries are double. Hach tube arises about the level or a 
little behind the level of the hinder end of the cervical glands. 
One of them runs, with but slight undulations, straight to the 
“ovejector”” which opens by the vagina, situated about one-sixth 
of the body-length from the hinder end, the other passes the vagina 
and reaches back almost to the anus; it then doubles forward 
again and opens into the posterior ‘“ ovejector.” 
The anterior end of each ovary contains undifferentiated 
protoplasm, but soon eggs begin toappear. At first these are very 
flattened, like a pile of coins, much broader than they are long; 
then they become thicker, and, finally, three or four times longer 
than they are broad. The rounded nucleus is in every stage 
very conspicuous. It is impossible to say precisely where the 
ovary ceases and the oviduct begins. We find the long cylindrical 
cells rounding themselves off and an egg-shell beginning to appear. 
By this time fertilization must have taken place, but I have not 
seen any spermatozoa in the oviduct. The oval cells usually he 
at first with their long axis at right angles to the longitudinal 
axis of the oviduct; then, when a little older, they lie obliquely, and, 
finally, they come to lie with their long axes parallel to that of the 
duct, in which position they are most readily swallowed by the 
‘“‘ovejector.” The anterior and the posterior oviducts usually 
contain one, two, or three unsegmented ova; then come some six 
to eight segmented eges representing as a rule the stages with two, 
four, eight, sixteen, thirty-two, sixty-four, and sometimes a hundred 
and twenty-eight blastomeres. One or two of these stages may be 
represented by two ova, but in any case the segmentation must 
be very rapid. 
The lower end of the oviduct is lined by what in optical section 
appear to be high columnar cells with very granular disintegrating 
borders. These seem to be secreting something. The walls of 
the oviduct pass suddenly into the ‘‘ ovejector,” which consists of 
three parts: (a) The most internal is somewhat funnel- or trumpet- 
shaped, its wider mouth is continuous with the walls of the oviduct 
and is crenellated ; the funnel is richly supplied with both longi- 
tudinal and oinetler fibres; not infrequently it contains an egg. 
(6) The second chamber of the “ovejector” is spherical, very trans- 
parent, and is marked by the presence of a large number of radiating 
muscle-fibres running from the periphery to the limits of the lumen. 
The contraction of these fibres would enlarge the lumen and suck 
the egg on. (c) The third chamber of the ‘“ovejector” is thin- 
railed, with a chitinous lining. It frequently shelters an egg. 
At its outer end it narrows, and uniting with the similar narrow 
end of its fellow it forms an extremely short vagina which opens 
to the exterior by a longitudinal slit, the edges of which are 
also crenellated. 
The ova are laid in the fluid contents of the host’s ceca, in 
which they are frequently found floating. We have found 
