476 MARINE INVERTEBRATES 
little rough; color olive-green. The animal is often attached to rocks 
more frequently to eel-grass and seaweeds, and is sometimes so crowded 
as to form large clusters. Found from Maine to North Carolina. 
M. pellucida. Body nearly globular, about an inch in diameter, 
smooth, clean, and translucent, the intestine showing through the test. 
The two tubes are large, swollen at the base, and divergent. The animal 
lives free in the sand, and is found from Massachusetts to North 
Carolina. ; 
M. arenata. Body somewhat compressed laterally; test thin and 
covered completely with sand, which is closely adherent; about three 
quarters of an inch in diameter; tubes short and wide apart. Found on 
shelly and sandy bottoms of bays and sounds. 
Genus Cynthia 
The animal is attached, the body coriaceous, and the orifices 
four-lobed. Frequently associated in groups, the individuals 
often differing in color. 
C. pyriformis. Body globular, or oblong when extenaed; hard, 
velvety, whitish surface, with pink cheeks; orifices on prominent pro- 
tuberances on the upper surface. It lives in clear, deep water on rocks, 
and is sometimes found at low-water mark on the northern New England 
coast. Commonly called the sea-peach. (Plate LXXXV.) 
C. partita. Body oblong; attached; test horny and wrinkled ; rusty- 
brown; apertures square, on prominent tubes marked with triangular 
spots of white and purple; diameter one inch. Found on the piles of 
wharves and on shelly bottoms in shallow water; also on the under side 
of stones when they are much flattened. 
C. carnea. Test low and flat, with a thin margin; adherent by a very 
broad base ; orifices small, square, slightly prominent; red or flesh-color. 
Found in deep water on stones and shells on the northern New England 
coast. , 
Genus Boltenia 
Body more or less globular, on a long stem; fixed; orifices on 
the side. 
B. clavata. Body long, wrinkled, leathery, on a long stalk, resem- 
bling the flower of lady’s-slipper (Cypripedium) ; two cross-shaped ori- 
fices wide apart on the side; yellowish in color; attached to stones in 
deep water, but sometimes washed ashore in storms. The stalks are. 
often covered with polyzoans and hydroids. (Plate LXXXV.) 
GEenus Ascidia 
Test gelatinous or cartilaginous; attached; it grows in bunches 
under stones at low-water mark. Sometimes it is variously col- 
