164 



COLLEGE ZOOLOGY 



7ie.ru '.I 



*an..cxeret its parasitic 



habits. There 

 is no alimentary 

 canal, the di- 

 gested food of 

 the host be- 

 ing absorbed 

 through the 

 body- wall. The 

 nervous system is 



FIG. 108. A proglottis of the tapeworm, Tcenia solium, similar to that 



with mature reproductive apparatus, can.excret, longi- ~ Planaria and 

 tudinal excretory canals with transverse connecting 



vessels ; gl.vit, vitelline or yolk-glands ; nerv.l, longi- tne liver-nuke, 



tudinal nerves ; ov, ov, ovaries ; por.gen, genital pore ; Kii t -not CQ well 

 schld, shell-glands; uter, uterus; vag, vagina; vas.def, vas 



deferens. The numerous, small, round bodies are the developed (Fig. 



lobes of the testes. (From Parker and Haswell, after T ~o ^OYI\ J\ 



_ , J. VJO. [v&r J. ) 



Leuckart.) ' 



Longitudinal ex- 



r.retnry tubes, with branches ending in flame-cells, open at the 

 posterior end and carry waste matter out of the body (Fig. 108, 

 can. excret.). 



A mature firoelottid is almost completely filled with reproduc- 



tive 



these 



n 



are shown 

 Figure 108. Sper- 

 matozoa originate 

 in the spherical 

 testes, which are 

 scattered about 

 through the pro- 

 glottis; they are 

 collected by fine 

 tubes and carried 

 to the genital pore 

 (por.gen.) by way 

 of the vas deferens 



FIG. 109. Stages in the development of the tape- 

 worm, Tania solium, to the cysticercus stage, a, egg 

 with embryo, b, free embryo, c, rudiment of the- 

 head as a hollow papilla on wall of vesicle, d, bladder- 

 worm (cysticercus) with retracted head, e, the same 

 with protruded head. (From Sedgwick, partly after 

 Leuckart.) 



