IO2 JOSEPHINE RANDALL AND HAROLD HEATH. 



that gives off a strong nerve which may be traced a short distance 

 posteriorly, and in the opposite direction a single connective 

 leads from it to the cerebro-pleural ganglia, as indicated in PI. I., 

 Fig. i, v. At various points throughout the body it is possible 

 to discover nerve bundles, but in every case it has been impossible 

 to determine their origin. 



In the three animals examined there is no sign of a testis, 

 though the seminal receptacle of one- individual contains a con- 

 siderable number of spermatozoa. These last named elements 

 possess almost spherical heads measuring approximately 0.004 

 mm. in diameter. Nuclei of somewhat similar appearance may 

 be detected here and there in the follicles of the reproductive 

 gland, but their close resemblance to those of the connective 

 tissue cells renders the determination uncertain. If self-fertiliza- 

 tion does not occur in this species it is difficult to understand the 

 method of sperm transfer especially in those examples where but 

 one parasite occurs in the host which completely envelops it. 



The ovary, occupying fully half of the visceral mass, consists of 

 a large number of follicles united directly or indirectly with the 

 duct leading to the exterior. In a mature condition the central 

 portions of each follicle are packed with fully developed ova, 

 while numerous cells in the earlier stages of formation bound the 

 periphery. About the center of the visceral mass the common 

 chamber, communicating with the ovarian follicles, narrows 

 anteriorly and the short resulting tube, after a somewhat twisted 

 course, unites (elliptical stippled outline, PI. I., Fig. 2) with the 

 definite gonoduct leading to the exterior. This last-named canal 

 consists of three divisions corresponding to the albumen and 

 mucous glands and the seminal receptacle in oilier species of 

 gastropods. The canal from the ovary unites with the albumen 

 gland which extends posteriorly as a pouch of considerable size. 

 Its walls arc relatively thick, and are fashioned into a few promi- 

 nent folds, consisting of relatively slender cells, whose vacuolated 

 secretion stains lightly with Delafield's hsematoxylin. Slightly 

 anterior to the oviduct connection, a cone-shaped seminal 

 receptacle (PI. I., Fig. 2, r) is attached to the albumen secreting 

 section. Its epithelial lining is developed into a large number of 

 folds between which there are quantities of spermatozoa, that 



