BY S. J. JOHNSTON. 323 



lobes. It is situated close under the dorsal surface (Fig. 59), 

 on a level with the ventral sucker and to one side of it, nor- 

 mally on the right side, but in ten per cent, of the specimens, 

 it lies on the left side. In any case, it lies on the same side as 

 the posterior testis. In the amphitype, not only are the ovary 

 and posterior testis placed on the left side, but the first postero- 

 lateral uterine loop runs on the right side instead of the left. 

 The oviduct comes off from the inner surface of the ovary, and 

 runs towards tlie middle line, being very soon joined by a 

 canal coming from the enormous receptaculum seminis (Fig. 

 61). Immediately after this, it is surrounded by the cells of 

 the shell-gland, a comparatively large mass of cells lying to 

 one side of the ovary : and in this part of its course, it also 

 receives the main duct of the yolk-glands. The receptaculum 

 seminis, of relatively enormous size, up to 0-68 mm. in dia- 

 meter, is pretty circular in ventral view, and lies on the same 

 level as the ovary and ventral to it, with the ventral sucker 

 generally about its middle. There is no Laurer's canal. In 

 the next part of its course, the uterus is generally filled with 

 spei'matozoa, and this portion may be looked upon as the re- 

 ceptaculum seminis uterinum. Then, as the ixterus, it runs 

 backwards to the extreme posterior end of the body as a 

 median descending loop, which is sometimes pretty straight, 

 but, in most older specimens, exhibits several spiral coils, 

 some of which, in front of the testes, reach the lateral mar- 

 gins of the body (Fig. 57). On reaching the posterior end, 

 the characteristic postero-lateral loops run along the margins 

 of the body, first to the left, then to the right. These postero- 

 lateral loops do not reach as far forwards as the ovary, and, 

 in old specimens, tend to be coiled (Fig. 11). At the end of 

 the right, descending, postero-lateral loop, the uterus turns 

 forwards again in the middle line, forming the median as- 

 cending loop, which, as far as the ventral sucker, closely re- 

 sembles the form of the descending median loop. In front 

 of the ventral sucker, in a number of closely placed transverse 

 coils, winch generally extend to the outer borders of the 



