328 ANIMAL PARASITES. 



in both sexes, a narrow, short tube ; which, however, very soon 

 acquires a greater diameter, so that the intestine in these places 

 is about 0-2 mill, in breadth. In the male, the intestine then 

 runs down in a tolerably straight, or, at the utmost, simply con- 

 torted course, and with its diameter remaining nearly the same, 

 on the inner side of the worm ; that is to say, on the side 

 towards which the caudal extremity of the male bends round. 

 About the point where the penultimate third of the abdomen 

 passes over into the last third, this intestine again narrows itself 

 into a very thin tube, which runs obliquely across the worm as far 

 as a little beyond the middle, and near to the outer side, where 

 it opens and projects a considerable piece into a large, strongly 

 muscular, tubular sac, near a second canal, which is also very 

 narrow, and runs more directly downwards. The two narrow 

 canals are closed at their points of opening into the large mus- 

 cular sac, with loop-like or valvular contrivances, by which the 

 retrogression of the contents of the large sac into the canals 

 opening into it, is certainly prevented. This muscular sac 

 forms an apparatus which serves the male sex as a common cloaca 

 and seminal efferent duct, of which we shall speak again under 

 the sexual organs. In the male, consequently, the intestinal 

 canal ceases some distance before the caudal extremity, and the 

 excrements pass out through the cloaca just mentioned. In the 

 female the intestine runs in simple contortions, directly, and in a 

 straight line, into the anus, and is of the same calibre throughout 

 as far as the anus itself, which usually presents the appear- 

 ance of a cleft, produced by the assistance of muscles or con- 

 tractile tissue occurring in that place. 



The sexual apparatus of the male consists of a simple penis, a 

 funiculus spermaticus or testicle which opens into the above- 

 mentioned tubular sac, and an appendix copvlatorius. I was 

 unable to find the commencement of the organ which forms the 

 semen, as it conceals itself behind the penis and the common sac 

 just referred to; and I could not follow it any further than to 

 the point indicated on PL VII, fig. 1, between i, &,and e, which, how- 

 ever, we may perhaps consider as the blind extremity of the testicle. 

 From this point the organ for the preparation of the semen rises 

 upwards, gradually becoming wider behind, and beneath, and close 

 to the intestinal canal, in undulatory curves, up to the short, canal- 

 like, contracted part of the intestine, which lies between the an- 

 terior extremity of the stomach and the csecal, yellow appendages 



