BY S. J. JOHNSTON. 333 



generally of two turns, lying in the base of the cirrus-sac. The 

 ejaculatory duct (Fig. 73) opens out of the anterior end of 

 the vesicula seminalis, and traverses the penis, which is fairly 

 well developed. The cirrus-sac is well developed, with muscu- 

 lar walls ; the prostate is represented by glandular cells lying 

 in the parenchyma, within the cirrus-sac. 



The oviduct, passing off from the inner- side of the ovary, 

 runs towards the left side of the body, and has connected with 

 it, in this part of its course, the receptabulum seminis, 

 Laurer's canal, the yolk-duct, and the shell-gland, in the 

 order named, beginning at the ovary. The receptaculum semi- 

 nis is rather small, in all the specimens sectioned containing 

 sperms : Laurer's canal is short, running almost as a straight 

 tube to the dorsal surface, where it opens near the middle line. 

 The shell-gland, or gland of Mehlis, is a compact mass of large 

 glandular cells surrounding the oviduct, near the place of 

 opening of the yolk-duct, just beyond the exit/ of Laurer's 

 canal. 



The uterus passes down to the extreme posterior end of the 

 body, in a number of coils passing transversely across the 

 body, and lying near the dorsal surface, ascending in the same 

 manner by a number of transverse loops lying near the ventral 

 surface to the left side of the ventral sucker, whence it runs 

 forwards to the genital opening, in a course parallel to the 

 cirrus-sac. The terminal part, the metraterm or vagina, is 

 provided with well-marked, muscular walls (Figs. 72,74). The 

 loops of the uterus fill up all the body-space behind the genital 

 glands, not occupied by the intestine and excretory vesicle. 

 The follicles of the yolk-glands (Fig. 72) are moderately large 

 (0084x0035 mm.), oval or pear-shaped, and occur in a 

 triangular patch, on each side, in the anterior part of the 

 body. There are about 35 follicles in each group. They do 

 not extend inwards beyond the intestinal limbs : anteriorly 

 they extend as far forwards as the posterior border of the oral 

 sucker, whilst posteriorly they do not reach beyond the ovary, 

 generally not so far as its anterior border. In the sections, the 



