The Rot in Sheej). 
107 
cation with it ; if so, we see no reason to doubt that it is here 
that impregnation takes place, and that the whole of the sper- 
matic fluid finds in this place its proper outlet. 
We are aw<are that a different opinion prevails among helmln- 
thologists, some of whom, however, speak doubtfully on the 
point ; and we are also not unmindful that our statement 
assigns no function to the so-called " vasa deferentia " and 
generative appendage, or " intromittent organ " {i, fig. 7 , and a, 
fig. 8) in the facundating process. One fact among several others 
which points to this conclusion is that the ova are seen covered with 
their membranous cases when issuing from the "germ stock," to 
enter the uterus (see description of these parts, p7-eceding page). 
Now it is evident that before being so covered their impreg- 
nation must have been effected. But supposing, on the contrary, 
the fopcundating fluid of the male organs to be ejected into the 
mouth of the oviduct, by being first conveyed, through the action 
of the " vasa deferentia," into the receptacle (b, fig. 8), which 
lies in the sheath (d, fig. 8) of the supposed intromittent organ, 
it is evident that it must traverse the entire convolutions of the 
uterus, pass all the perfected ova, and descend into the " germ 
stock " to exert its special purpose. This, at any rate, is a cir- 
cuitous course, although none the less possible merely on that 
account. The other view, however, has simplicity if not posi- 
tive verity for its support ; it leaves, nevertheless, an office to 
be assigned for the so-called "vasa deferentia" and the other 
organs connected with them, of an entirely different character, 
unless absolute copulation between two distomata does take place. 
We speak with some hesitation and with much deference to 
eminent helminthologists, when we say that the " vasa deferentia " 
(d d, fig. 7, and c c, fig. 8), which have their origin near to the 
caudal extremity of the entozoon, may possibly secrete a fluid 
which is carried into the receptacle {b, fig. 8), lying within the 
sheath of the generative appendage, hence to be conducted into 
the oviduct during the well-known retraction of the organ, to 
furnish the earthy materials necessary for the proper formation of 
the shells of the numerous ova existing within the uterus. From 
the peculiar arrangement of the parts it seems easy for the 
opening of the duct belonging to the appendage to be brought in 
contact with the mouth of the oviduct, when the organ is partially 
retracted into its sheath, and it is probable that in the act of 
retraction the materials are made to enter. That there must be a 
great demand for such matter all must admit who have carefully 
studied the ova of the Distoma. Such a view, of course, pre- 
supposes that the vasa defei'entia are unconnected with the testes, 
which, by-the-bye, far exceed them in size ; not that this fact 
of itself negatives the opinions which are generally entertained, 
