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 XLVIII.) 
Genus Planocera 
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: | 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 
('' 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. 
