PROGRESS OF MICROSCOPICAL SCIENCE. ZT 
Dr. Spencer Cobbold, fully confirming the author’s views. There is an 
excellent plate too, representing the natural size (half-inch), and 
also showing its minute anatomy, of which the following is an 
abstract :—1. Oral extremity. There is a deep, circular, cup-shaped 
cavity, having the proper opening of the mouth at its base. From 
the mouth proceeds a tube that dilates almost immediately to form a 
pharynx, directly beyond which the tube bifurcates, sending a division 
along each side to the caudal extremity, where they terminate in 
ceecal ends without any branching or subdivision. These tubes are 
no doubt the stomach. The contents are small, granular, usually 
refractive particles. 3. The water-vascular system. It commences 
at the extremity of the broad or caudal end, and after coming nearly 
in a line with the blind extremities of the stomach tubes, it dilates a 
little, and proceeds onwards in a slightly crooked course as far as 
nearly one-third the length of the animal. It then divides into two 
branches, which proceed one to each side until they traverse the 
stomach tubes, when they subdivide into two branches, one of which 
proceeds forwards and the other backwards, just external to the 
stomach. The contents are small, highly refractive particles. The 
organs concerned in reproduction occupy the greater part of the 
animal. 4. The ovary —a dark oval-shaped body lying obliquely 
with regard to the long axis of the parasite, and almost entirely to 
one side of the median line, from a little beyond which it extends to 
the stomach tube. It varies in size and shape according to the 
quantity of its contents. Attached to its end next to the oral extremity 
of the animal, is an irregular saculated pouch. It would appear to 
retain the miniature eggs until they are sufficiently developed for 
extrusion into the uterus. 6. Ducts of the yelk-forming glands. 
They proceed straight from the uterine pouch one to each side of the 
animal, and spread out into two beautifully formed bodies, the yelk- 
forming glands, situated between the stomach tube and the outer 
edge of the animal, on both sides, as far forwards as the neutral 
acetabulum and as far backwards as the ovary. Their contents are of 
a dark brown, but after being treated for some time with a solution 
of caustic soda, they become of a light red colour. 8. The uterus. 
A long irregularly branched tube occupying nearly the whole space 
between the gastric tubes from the uterine pouch behind to the 
neutral sucker in front. In every specimen it has a dark brown 
colour from the multitudes of contained eggs. It opens externally 
upon the surface of a small papilla. 10. The two testes. They are 
situated the one behind the other in the posterior third of the animal. 
They present a beautiful dendritic appearance that varies in its 
details of form in different individuals. It is very difficult to trace 
the course of the vasa deferentia. They seem to form a common duct, 
the end of which is modified to serve as an intromittant organ; but 
my observations on this point are not quite satisfactory. The eggs 
are very small; they have a brown colour, which is due not to the 
shell or covering of the egg, but to the yelk-granules. The operculum 
of the egg is colourless. It is situated at one end of the egg, and 
seems to be easily detached, as it is not seen on many eggs, even 
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