166 MARINE INVERTEBRATES 



matter collects in the main intestine and is forcibly ejected by 

 the pharynx. Numerous eyes are collected in groups on the 

 anterior dorsal surface, or arranged around the margin of the 

 body. The eggs are laid in shell-like cases, and cemented 

 together in plate-like masses or in spirals, and attached to shells 

 or stones. (Plate XL VIII.) 



GENUS flanocera 



P. nebulosa. One half of an inch wide and three quarters of an inch 

 long, circular or elliptical in shape ; very flat and thin ; olive-green 

 on the dorsal surface, with a line of darker color on the posterior end, 

 and whitish retractile tentacles on the back. Found creeping on under 

 side of stones in tide-pools. 



GENUS Stylochopsis 



S. littoralis. About one half of an inch long; changeable in form, 

 from broad oval to elliptical ; color pale green, veined with a lighter shade 

 on the dorsal side, flesh-colored on the ventral surface ; numerous eyes ar- 

 range" I in irregular rows near the margin and in groups in front of the 

 tentac es, also clusters of eyes on the tentacles. Found under stones 

 between tide-marks. 



GENUS Leptoplana 



L. folium. Body flat ; margin thin and undulated ; shape leaf-like, 

 but changeable ; about one inch long and one half of an inch wide ; color- 

 pale yellow, veined with a deeper shade ; eyes in four groups near the 

 anterior end. 



ORDER TRICLADIDA 



C" Three-branched " ) 



The triclads are divided into three groups : those of the fresh- 

 water ponds and streams, those of the land and sea, known as 

 planarians, and those of the sea. The planarians are the most 

 interesting worms in the order. The triclads differ from the 

 polyclads in being elongate in form and in having the intestine 

 in three branches instead of in many. The mouth is midway in 

 the length of the body, on the ventral side, and from it protrudes 

 a pharynx, which is cylindrical or bell-shaped, and is capable of 

 great dilatation. With the pharynx the worm, which is wholly 

 carnivorous, envelops other worms, crustaceans, or any animal 

 food. Several species are found on the under side of stones in 

 tide-pools. 



