Japanese Freshwater Triclads. 



19 



'V 



pharynx, cylindrical in shape, is inserted at about the middle of 

 the body-length. Tbe anterior main gut trunk is provided with 

 -8-9 pairs of lateral branches, while the posterior trunks each send 

 out 14-17 external branches and 

 about as man}^ very small internal 

 branches. 



Of the excretory canals I 

 have been able to obtain no more 

 insight than a few loops at some 

 points in the dorso-lateral parts 

 of the body. 



Nervous System. — The brain 

 is a bilobed organ, each half of 

 which, besides the optic nerve, 

 gives rise to five forwardly directed 

 sensory nerves, breaking up into 

 branches, and some lateral nerves. 

 Posteriorly each brain-mass is 

 continuous with one of the longi- 

 tudinal nerve cords which extend, 

 pursuing a parallel course, to the 

 hind end of the body, and are 

 connected by numerous trans- 

 verse commissures. The cord of 

 either side is also connected with 

 the marginal nerve of the same 

 side by means of a series of lateral 

 nerves given ofï usually from the 

 cord at points opposite to the 

 union of the latter with transverse 

 commissures. 



Oenital Organs. — Tlie com- 

 mon genital aperture is situated 

 at about the middle of the pos- 

 terior third of the body. It leads 

 into the small vestibulum, which 



pn- 



- 7n 

 -Sr 



mm 



Test fig. 6. Diagrammatic repre- 

 sentation of the organization of Pla- 

 naria painllifera I.i. et Kab., as seen 

 from the dorsal side. 

 e eye, gv genital vestibulm, i intestine, 

 m mouth-opening, or ovary, 2)7i pharynx, 

 t testis. 

 Other letters as in text figs. 2 and 5. 



