^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 radiating 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. A similar or perhaps identical species occurs on the North Pacific 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 bordered with granules. The arms are fringed with rows of thick, compressed, obtuse spines, generally six in each row. The under sides 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 [pg216] in length and thread-like in size. These long, slender arms have, on both the upper and under surfaces, a row of overlapping plates, and are fringed with small spines, three in a row. The color is gray or whitish, sometimes marked with darker gray or brown. (Plate LV.) GENUS ^Ophiocoma^