1912.| NATURAL SCIENCES OF PHILADELPHIA. 465 



translucent spot marks the position of the brain. The mouth is 



situated almost exactly in the 



centre of the body. Tentacles • 



are lacking. The penis is placed 



about one-third of the distance 



from the mouth to the posterior .*** *.;, * • 



end, well behind the pharyngeal •«?'*%$ * ; **; 



/ 



:» 





• 



pocket, and is directed back- #">;•:♦ .VJ«* 



ward. The eyes (text fig. 2) are 1*i« •„ 'tf i' " !**!• "* 



arranged in four groups, a com- 

 paratively long pair of approxi- ./*J *•*• * »*••• ' >*^'l 



mately 30 eyes in each adjacent . /• ^Jg^ 



to the brain, and a small more . % 



rounded, laterally placed pair ** 



comprising about 30 eyes in each Fig. 2.— Eyes of Leptoplana rupicola. 

 cluster. No eyes occur elsewhere 

 in the body. 



The pharyngeal pocket, scarcely one-third the length of the body, 

 is supplied with numerous irregularly lobed diverticula, correspond- 

 ing in a general way to the folds of the pharynx. The main gut is 

 of about the same length as the pharynx, though is much more 

 slender in outline, and is provided with approximately fifteen pairs 

 of lateral intestinal branches whose subdivisions give no signs of 

 anastomosing. 



The brain is placed very nearly one-fourth of the body length 

 from the anterior margin of the body, and as described previously is 

 associated with two pairs of eye clusters. The ventral system of 

 nerves is fairly well defined and conforms to the usual type. 



The testes are ventral, and what appears in sections to be an 

 anastomosing system of sperm canals unites them with the vasa 

 deferentia. The last-named tubes (PI. XII, fig. 3) are continuous 

 across the mid line immediately posterior to the female reproductive 

 pore, and from this point extend forward, diverging somewhat, as 

 they become increasingly anastomosed. Opposite a point slightly 

 anterior to the level of the mouth this elaborate network bends upon 

 itself, skirts the margin of the pharynx, and not far behind the 

 posterior end of the gut each becomes reduced to a single duct which 

 sweeps inward and forward to fuse with its fellow in the mid line. 

 This median duct (PI. XV, fig. 22) proceeds in an anterior direction 

 for a short distance, then bends upon itself and immediately enters 

 the small but muscular seminal vesicle. Emerging from this at the 



