268 s. GOTO. 



In the former he calls the prostate gland and the internal cavity 

 of the penis " vésicules séminales," and the receptaculum 

 seminis " vésicule copulative " [p. 32], while in the explanation 

 of the figure relating to the point [pi. Ill, fig. 1] he calls the 

 latter ** vésicule séminale interne," and the prostate gland alone 

 " vésicule séminale." 



The penis is a hollow, pear-shaped body with a comparative- 

 ly thin wall, lying in the expanded blind end of the genital 

 atrium. The terminal portion of the vas deferens enters its 

 wall at its hind end, and expanding slightly, forms a sort of 

 seminal reservoir, as in many species of Tristomum. The internal 

 cavity of the penis communicates with that of the prostate gland 

 by means of a short narrow canal, and is usually filled with a 

 finely granular mass, the secretion of the prostate gland. 



The prostate gland is an irregularly rounded, vesicular organ 

 lying directly behind the penis. In the specimens examined by 

 me the internal cavity was almost completely filled with a finely 

 granular mass staining deeply in carmin. The structure of its 

 wall could not be made out in ray sections, but I think I may 

 safely assume that the granular mass just referred to has been 

 secreted by the protoplasmic wall. 



The receptaculum seminis lies in the proximal portion of 

 the oviduct at a short distance from the ovary, and is, as cor- 

 rectly observed by van Beneden, a vesicular organ consisting of 

 five to six lobes, and opening directly into the oviduct. Between 

 it and the ovary, but nearer the former, the oviduct receives the 

 unpaired yolk duct coming from the yolk reservoir, from which 

 it originates on the dorsal side a little towards the anterior, and 

 proceeds slightly backward on its way to the oviduct. In most 

 species of Tristomum and Epibdella the shell glands open into 



