1912.] 



NATURAL SCIENCES OF PHILADELPHIA. 



475 



•i 





The mouth (PI. XV, fig. 17) is situated between one-iourth and 

 one-fifth of the length of the body from the anterior end. The 

 ventral sucker is placed approximately three-sevenths of the body 

 length from the posterior end. The penis is between one-third and 

 one-fourth of the length of the animal from the anterior margin, 

 immediately behind the pharynx, 

 and is directed forward. Nuchal 

 tentacles are lacking, while the 

 marginal tentacles appear as some- 

 what thickened flaps. Eyes, indefi- 

 nitely grouped into two clusters 

 (text fig. 5), occur between the 

 tentacles, while a second pair of 

 about fifteen eyes each and more 

 clearly differentiated occupy the 

 brain area. It is interesting to 

 note that dorsal papillae (PI. XIII, 

 fig. 11), of small size but clearly 

 defined, exist in this species, being 

 especially abundant in the anterior 

 part of the body. 



The mouth (PI. XV, fig. 17) 



Opens into the much-folded pharynx Fig . 5.— Brain and tentacle eyes of 

 which is between one-sixth and Ticheniplana lepida. 



one-seventh as long as the body. 



Somewhat behind the external mouth the inner mouth leads to the 

 main chamber of the gut, a long and spacious structure provided 

 with approximately fifty pairs of lateral branches. These last- 

 named subdivisions branch frequently and form a highly anastomos- 

 ing system. 



The brain is situated half-way between the anterior end of the 

 body and the mouth, but the nerves to which it gives rise are very 

 indistinct and little attempt has been made for this reason to work 

 out the system in detail. 



The testes are ventral and rather uniformly distributed. There 

 is some evidence that these organs are connected by an anastomosing 

 system of sperm capillaries, which eventually fuse to form the vasa 

 deferentia (PI. XV, fig. 17), relatively large, convoluted canals 

 extending along the margins of the gut throughout most of its 

 length. They arch inward to enter the seminal vesicle (PI. XVII, 

 fig. 36), almost spherical in form, without the formation of a common 



