TBICHOCEPHALUS. 73 



cavity of the body of tlie animal. Immediately beyond the last 

 sacculus the canal contracts and is received into the dilated head 

 of the abdomiaal intestine, forming in this situation a muscular 

 valve. The abdominal intestine then pursues its course along the left 

 side and inferior border of the cavity of the abdomen to the anus. 

 This intestine is thick, and its lining membrane is studded with dark 

 rugge, "which remind us of the rugous appearance of the gizzard of 

 a bird. They are largest and most prominent in the middle third 

 of its extent, and are arranged in longitudinal hues. At a short 

 distance from the extremity of the tail the intestine suddenly con- 

 tracts and becomes transparent, and is then continued in a straight 

 line to the anus. This contracted and transparent portion of the 

 intestine corresponds with the rectum. The anus is situated 

 upon the lower or curved border of the animal, close to its blunt 

 termination. It is an elliptical opening of moderate size, closed 

 by a strong sphincter muscle." This description accords in all 

 essential particulars with that which has been observed in Tricho- 

 cephalus dispar, but Mr. WUson does not accept the generally 

 received view as to the functional character of the different parts. 

 Without dwelling on this matter, I will merely observe, in passing, 

 that the portion of the canal which he calls the " dilated head of 

 the intestine " is manifestly the true stomach of Kuchenmeister 

 and others. The mode of termination of the ahmentary canal in 

 the male is somewhat peculiar, the true anus being placed high 

 up at a very considerable distance from the external or general 

 cloacal outlet, the wall of this common tube becoming intimately 

 blended with the sheath of the penis at a httle distance above the 

 final opening. Wilson's and Kuchenmeister' s descriptions are 

 quite clear and consistent, and I have therefore abandoned my 

 previous notions where they were at variance with their authority 

 on these points ; but I have entire confidence in the results of my own 

 examinations as regards the sexual organs, to which structures 

 my investigations were specially directed. 



With reference to the organs of generation in the female, 



