1912.] NATURAL SCIENCES OF PHILADELPHIA. 473 



actively for short distances. Dorsally the color is dark, marbled 

 brownish-gray varying to almost black. A pale yellow streak 

 extends along the median line in the region of the pharynx. This 

 is bordered on each side by a dark, brownish line of similar length, 

 which fades into the ground color. On the ventral surface of the 

 animal pigment is lacking, the tissues appearing clear white and of 

 such thickness that the internal organs are invisible in living material. 



The largest specimen is long oval (PI. XII, fig. 7) in outline and 

 measures 19 mm. in length by 9 mm. in width. The penis is directed 

 backward. Four distinct eye clusters (PI. XVIII, fig. 42) occur 

 associated with the brain, an elongated pair composed of small 

 eyes on each side of the brain, and a more or less circular pair com- 

 prising larger ocelli located slightly behind the level of the brain. 



The mouth, approximately central, opens into the much-folded 

 pharynx (PI. XII, fig. 7) that is nearly half as long as the body. 

 A short distance anterior to the external mouth the inner mouth 

 leads into the spacious and much elongated main gut provided 

 usually with fourteen pairs of variously shaped intestinal branches. 

 These last-named subdivisions branch dichotomously and give no 

 evidence of forming an anastomosing system. 



The brain is located about one-sixth of the body length from the 

 anterior end of the animal, but as neither it nor the branches arising 

 from it are distinct, no attempt has been made to study this system 

 in detail. 



As usual the testes are ventral and are thickly distributed, espe- 

 cially near the middle of the body. The vasa deferentia form a 

 U-shaped loop (PI. XII, fig. 7), the bow of which passes immediately 

 behind the female reproductive pore, while anteriorly the two limbs 

 turn sharply inward, and coursing parallel to the outer arms for half 

 their length again bend quickly, and after pursuing an anterior 

 course for a short distance expand to form two seminal vesicles 

 (PI. XV, fig. 23). These converge into a common duct., the ductus 

 ejaculatorius, that after 

 piercing the granular ^ g £ 



gland passes into the 

 base of the penis. This 

 latter organ is of the 

 usual type, directed 

 backward and opens to 



the exterior at a point v - . T .. ,. , ,. ,, , .. , 



1 big. 4. — Longitudinal section through central re- 



about one-fifth the body productive apparatus of Phylloplana litoricola. 



