BRITTLE-STARS 215 
Some species may be found near low-water mark under stones 
and in clusters of mussels, and often in seaweeds, thrown up 
from deep water, on the shore. 
ORDER EURYALIDA 
Genus Astrophyton (Plate LV) 
A. Agassizii. This very singular ophiuran is commonly called the 
basket-fish, from its resemblance to a basket when the tentacles are 
rolled up. Its body is covered with skin instead of calcareous plates. 
The body is thick and somewhat circular in form, with elevated radi- 
ating ridges on the upper side, and the skin is marked off in star-like 
divisions. From the. margin of the body extend five arms, which at 
once divide in a forking manner; each section again divides, and this 
division in pairs (dichotomous division) continues until the ends of the 
arms have become very numerous and attenuated. The arms are carried 
curled up or straight at will. In moving, the animal seems to walk on 
these branches as if on tiptoe, and in this position it forms a kind of 
net which entraps prey. The arms and prominent parts of the disk are 
yellow, and the depressed or membranous parts brown. <Astrophyton is 
six to eighteen inches in diameter. It is found off the northern New 
England coast. 
ORDER OPHIURIDA 
GENUS Ophiopholis 
O. aculeata. This is a common species, found in shallow water on 
the North Atlantic coast. Asimilar or perhaps identical species occurs 
on the North Pacifie coast. It is spotted purple or variegated in color. 
The upper surface of the body is covered with plates variously arranged, 
sometimes in the shape of a star, and each one is surrounded with small 
spines. The under side of the egg-sacs is covered with small spines. 
These sacs open by slits on each side next the arms, and have a rounded 
appearance, bulging out between the arms. The arms, which are long 
and attenuated at the ends, have on the upper side transverse oval plates 
surrounded by a border of flat, roundish granules. Sometimes the 
plates are divided into two or three pieces, when they are similarly bor- 
dered with granules. The arms are fringed with rows of thick, com- 
pressed, obtuse spines, generally sixineachrow. The undersides of the 
arms have large quadrangular plates slightly separated from one another 
and extending across the whole surface in regular, even rows. 
(Plate LV.) 
Genus Amphiura 
A, squamata. This very delicate species, found on shelly bottoms 
below low-water mark from New Jersey northward, has a body less 
than one quarter of an inch in diameter, with arms two inches or more 
