The Rot in Sheep. 



here that impregnation takes place, and that the whole of the 

 spermatic fluid finds in this place its proper outlet. 



We are aware that a different opinion prevails among helmin- 

 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 foecundating process. One fact among several others 

 which points to the correctness of our 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, preceding page). 



It is self-evident that before being so covered their impregna- 

 tion must have been effected. But supposing, on the contrary, 

 the foecundating 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 clear 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 deferentia 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, 



