POLYZOA 197 
much smaller and narrower than those of M. pilosa ; easily distinguished 
from that species by its manner of spreading and the absence of the one 
long hair. Common from New Jersey northward. 
M. tenuis. Common on pebbles, often covering their whole surface 
with a lace-like incrustation of very small oblong cells having a three- 
lobed aperture. Found in Long Island Sound and north to Cape Cod. 
Genus E’scharella 
E. variabilis. This species forms calcareous incrustations on shells 
or pebbles. The layers are thin, but eventually overlap one another, and 
the incrustation sometimes becomes an inch thick and resembles coral. 
The color of the living animal is dull red. The species ranges from Cape 
Cod to South Carolina, and is abundant in Long Island Sound. 
Genus Mollia 
M. hyalina. Cells subcylindrical, irregular, transparent, smooth, 
and more or less oblique. The species forms small circular disks on alge 
in tide-pools. 
Genus Cellepora 
a scabra. It forms branching, coral-like masses on slender red 
alge. 
©. ramulosa. Branches cylindrical, rough, dividing in a forking 
manner, spreading, two to three inches high, calcareous; cells urn- 
shaped, irregularly arranged, apertures contracted, long spine on the 
outer edge. It is found in deep water attached to shells, and in tide- 
pools, where it grows chiefly on Sertularia and other hydroids and on 
slender red alge. It ranges from Long Island Sound to Greenland. 
(Plate LI.) 
C. pumicosa. Cells urn-shaped, irregularly crowded together, form- 
ing a conglomeration of porous, brittle masses, not exceeding an inch in 
breadth, usually round when small, oblong and knobbed when large; 
spine on outer margin of aperture. It incrusts stones and the stems of 
Fucus. (Plate LI.) 
SUBORDER CTENOSTOMATA 
Genus Aleyontdium 
A. ramosum. Twelve to fifteen inches high; much branched; 
branches smooth, cylindricai, one third of an inch in diameter, usually 
crooked ; branches in a forking manner; color rusty-brown. Abundant 
in shallow water, attached to rocks, from New Jersey to Cape Cod. 
A. hirsutum. A species common on seaweeds, sometimes completely 
covering them, forming dirty, straw-colored, thick, cartilaginous crusts 
covered with numerous conical papilla. These are the cells, or zocecia; 
they are surrounded with spines. Circular yellow spots occur over the 
surface, which are clusters of eggs. A good-pocket-lens will show the 
cells, laid in beautiful order, and perhaps the extended tentacles. Found 
from Long Island Sound northward. 
