Ir 



-rod 



-M.? 



Fig. 5. Diagrammatic 

 view of the struc- 

 ture of Leptoplana 

 tremellaris as a 

 type of the Poly- 

 cladida. The body 

 is cut across the 

 middle to show the 

 relative position of 

 organs in trans- 

 verse section. In 

 the posterior half 

 the alimentary 

 canal has been bi- 

 sected and removed 

 from the left 

 side, to exhibit the 

 deeply placed nerv- 

 ous sheath (un) 

 and the male re- 

 productive organs. 

 br, Brain ; dp, 

 " diaphragm " ; e, 

 cerebral group of 

 eyes ; et, tentac- 

 ular eye - group ; 

 gr, marginal 

 groove ; gm, true 

 mouth ; Ig, lateral 

 gut - branch ; In, 

 longitudinal nerve 

 stem ; m, external 

 mouth ; mg, vuf, 

 main -gut, whole, 

 and bisected ; n, 

 sensory nerve sup- 

 plying the eyes ; 

 nn, nervous net- 

 work lying on the 

 ventral muscula- 

 ture ; n.s, lateral 

 nerve ; ocl, oviduct ; 

 ov, ovary ; pe, penis 

 (in section) ; ph, 

 pharynx ; pr, pros- 

 tate or " granule 

 gland"; sc, sucker ; 

 sg, shell-gland ; 

 te, testes ; vp, an- 

 terior unpaired 

 gut - branch ; ut, 

 uterus ; va, vagina 

 (in section) ; vd, 

 vas deferens ; ve, 

 vasa efferentia ; 6, 

 male genital pore ; 

 ?, female pore. 



