The Rot in Sheep. 



45 



The uterus. — This organ lies nearer to the ventral than to the 

 dorsal surface of the entozoon, and is therefore best to be observed 

 on that side. It stretches more or less across the body of the fluke 

 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,fig- 8, page 47) 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^fig. 7, and d, fig. 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 

 fig. 8), and this entirely without reference to their number within 

 the uterus. They therefore escape singly, but no doubt in very 

 quick succession, so that a considerable quantity are soon voided. 

 " It has been calculated that the uterus of the full-grown fluke 

 may contain upwards of 40,000 eggs." 



While in the uterus the ova undergo a singular change in colour 

 by their shells losing their original white condition and becoming 

 of a yellowish-brown hue. The shells also become harder and 

 thicker, as would appear from an earthy deposition within their 

 tissue, 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 crepi- 

 tating sound. The origin of this hardness is to our minds 

 somewhat doubtful, although we would not dispute 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 cir- 

 cumstance, 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 fj\ Jig. 7), being entwined and tw isted 

 in every possible direction. In many places they would appear 

 to have ccecal beginnings, which are more or less forked and 

 branched (gg^fig- 7). In size they exceed the duets belonging to 

 the female generative system, while their contents impart to them 

 a much paler colour. Some of these seminiferous tubes cluster 

 around the "genu stock" and have, we believe, a free commu- 

 nication with it ; if so, we see no reason to doubt that it is 



