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MANUAL OF ELEMENTARY ZOOLOGY 



pore lies on the middle line. The female bears a median 

 genital pore at about one-third of the length of the body 

 from the front end, on the ventral side of a region which is 

 slightly narrowed. The tail is curved downwards, slightly in 

 the female and strongly in the male. The anus lies below, 

 about a couple of millimetres from the hind end. In the 



Fig. 203. — Ascaris lumbricoides. 

 A, Male ; B, female. 



«., Anterior end ; an., anus; c, excretory pore ; g.o., genital 

 opening ; p., posterior end ; p.s., penial setae. 



male this opening serves also as a genital pore, and there 

 project from it a pair of penial seta. 



Internally, a spacious perivisceral cavity, which has all the 

 characteristics of a hamoccele (p. 230), separates a straight, 

 simple gut from a simple body-wall. The latter is made 

 up of three layers : a stout, smooth, chitinoid cuticle which 



