64 OS BORN. [Vol. II. 



the comparatively free life of P. anodontac and the possession 

 of eyes, in contrast with the absence of eyes in the strictly 

 endoparasitic P. lejwiri and its allies, the other genera of this 

 family. 



The location of the chief organs of the reproductive system 

 agrees closely with that indicated for P. lenoiri in the figure in 

 Bronn (PL XX, Fig. i) ; and it is also very similar to the 

 arrangements found in Aspidogaster. I have not been able to 

 trace all of the windings of the ducts by the section method ; 

 their intricacy has made it impossible to do so ; but I feel rea- 

 sonably sure of the identification of the portions which I have 

 introduced into the partially diagrammatic Fig. i. The sper- 

 mary is single. It is recognized by the presence of small sper- 

 matic cells, but no spermatozoa were recognized in any of the 

 sections. The organ is oval, large, and located about on a level 

 with the hind end of the intestine, and ventrally to it. The 

 nuclear material indicated, possibly, some activity in the tissue, 

 but no mitotic figures were visible. I have thought of two sup- 

 positions by which to account for their absence, viz,, the organs 

 may not have been in a state of activity at the time; and, second, 

 the methods of preservation may not have been adequate. I 

 found in staining that the presence of the cuticle interfered 

 with the action of reagents, and it is quite possible that the 

 germinal cells, if active, got into a state of rest before the rea- 

 gent used in fixation had had time to take effect. The almost 

 invariable presence of the embryos in the vagina seems to indi- 

 cate that the animal is mature and that, consequently, these 

 organs are or have been active. 



There is a single ovary. It lies on the right side of the 

 body (see Figs, i and 6), near the middle, and ventrally to the 

 intestine, and below the diaphragm. The vitellaria are also 

 conspicuous, lying scattered through the ventral portion of the 

 flattened body, near its margin. I have not as yet succeeded 

 in tracing the ducts which connect the different portions of 

 the female reproductive organs. The terminal portions of the 

 reproductive system have been identified with reasonable cer- 

 tainty. The generative opening is visible in the mid-ventral 

 line of section No. 23. This places it in front of the foot, in 



