1912.] NATURAL SCIENCES OF PHILADELPHIA. 477 



XVIII, fig. 40) occur on the anterior margin with a cluster of approxi- 

 mately eighty small eyes at the base of each. The cerebral eyes 

 form two rather long, closely approximated groups, with about fifty 

 medium-sized ocelli in each, located chiefly posterior to the brain. 



In the midst of the cerebral groups of eyes the mouth (PI. XIII, 

 fig. 16) occurs and leads into a long, spacious canal which may be 

 considered as a portion of the pharyngeal cavity. The unfolded 

 pharynx is tubular in form, but anteriorly it tapers to a fairly acute 

 point. In length it equals about one-seventh that of the animal. 

 Posteriorly it opens into a main gut of average size that usually 

 gives rise to four pairs of lateral branches, the most posterior of 

 which is some distance from the hinder end of the gut, thus forming 

 a terminal blind sac. The intestinal branches do not anastomose, 

 nor are the secondary branches numerous. 



The brain holds a position one-twelfth the body length from the 

 anterior end of the body, but owing to their indistinctness the course 

 of the nerves, to which it gives rise, has not been determined. 



In this species the testes, ventral in position, are clearly defined, 

 but the sperm canals are totally invisible. The vasa deferentia 

 are likewise somewhat ill-defined, but may be seen (PI. XIII, fig. 16) 

 in favorable specimens to arise about opposite the posterior end of 

 the pharyngeal chamber and to extend anteriorly to a point not far 

 behind the level of the mouth. Here they turn abruptly backward 

 and inward to enter the seminal vesicle (PI. XVII, fig. 37) at its 

 antero-ventral extremity. The seminal vesicle is more or less 

 heart-shaped, and is placed immediately in front of the pharynx 

 and ventral to the tube leading from the pharyngeal cavity to the 

 external mouth. Leaving the seminal vesicle anteriorly, the ejacu- 

 latory duct makes its way to the base of the penis where it receives 

 a short duct from the granular gland. This last-named organ is 

 small, spherical, and is located immediately in front of the seminal 

 vesicle. The penis is very short, in some specimens rather abruptly 

 pointed, and it opens into a chamber contained within the penis 

 sheath, which in turn opens into the antrum masculinum. This 

 last-named space communicates with the mouth. 



The ovaries contain, during the breeding season, an unusually 

 large number of ova and are accordingly very distinct, though the 

 ducts connecting them with the uteri are invisible except occasionally 

 in sections. The uteri (PI. XIII, fig. 16) originate approximately 

 half the distance from the ventral sucker to the posterior end of the 

 main gut. From this point, where apparently they do not fuse 



