106 
The Rot in Sheep. 
ance in determining the use of the " germ stock," about which 
authorities differ. The eggs are colourless before they reach the 
uterus, and have exceedingly thin cases or coverings. 
The uterus. — This organ lies nearer to the ventral than the 
dorsal surface, and is therefore best to be observed on that side. 
It stretches more or less across the body of the entozoon both 
beneath and behind the ventral sucker. It is liable, however, to 
great variation in size — according to the quantity of ova it 
contains. In some instances the ova lie in many parts of the 
organ as a single file, while in others they are crowded together 
and overlie each other in all possible directions, so as to have an 
appearance of being placed in a largely dilated cavity, rather 
than in a duct coiled and turned upon itself. From the uterus 
the oviduct {f,J>(/. 8, pa(/e 108) passes in a tortuous course by the 
side of, or occasionally partly behind, the ventral sucker, to reach 
the sheath of the male organ (i,Jig. 7, and d,ficj. 8), upon the edge 
of which it opens. This opening is with very great difficulty to 
be detected, and we have spent many a fruitless hour in searching 
for it, only succeeding now and then. 
The ova lie always along the oviduct in a single row (see 
Jig. 8), and this entirely without reference to their number within 
the uterus. They therefore escape singly, but no doubt with 
very quick succession, so that a considerable quantity are soon 
voided. While in the uterus the ova undergo a singular 
change in colour by their shells losing their original white con- 
dition and becoming of a yellowish-brown hue. The shells 
also become harder and thicker, as would appear from an earthy 
deposition within them, for when the ova are slightly pressed on 
a slip of glass they are found to have a gritty feel, and to 
give a peculiar crepitating sound. The origin of this hardness 
is to our minds somewhat doubtful, although we would not dis- 
pute that it may be due to the secretory function of the internal 
membrane of the uterus. It is sufficient in this place to allude 
to the circumstance, more especially as we shall presently return 
to it again. 
Male Organs : the Testes. — These organs occupy the central 
parts of the body, being bounded inferiorly and laterally by the 
yelk sacs and ducts, and superiorly by the uterus. They consist 
of a series of convoluted tubes, which seemingly follow no fixed 
plan of arrangement (see ff, Jig. 7), being entwined and twisted 
in every possible direction. In many places they would appear 
to have coecal beginnings, which are more or less forked and 
branched (g g, Jig. 7). In size they exceed the ducts belonging to 
the female generative system, while their contents impart to them 
a much paler colour. Some of these seminiferous tubes cluster 
around the germ stock," and have, we believe, a free communi- 
