Ophurans (Ophiurida), a family of star fishes in which the five rays are long, slender, flexible, and snake-like, whence the name; in some the arms are very fragile; the common name of the genus ophiura is sand star, from their habit of hiding in the sand. The viscera are confined to the central circular disk; the arms are not excavated in grooves below for the protrusion of ambulacral tubes; they swim and creep with facility by means of the spines or the arms. In ophiocoma the arms are so readily detached, at the will of the animal, that they are called " brittle stars." In the group of euryahe the arms are much branched; the genus astrophyton of the North American coast has so great a number of terminal subdivisions, like snaky hairs, that it has been called Medusa's head; it is also called fisherman's basket, from occasionally having, when caught in deep water, fish and other animals embraced in the numerous flexible rays. According to T. Lyman, there are more than a dozen species of ophiurans on the coast of the United States.

Serpent Star (Ophiopholis).

Serpent Star (Ophiopholis).

Astrophyton Agassizii.

Astrophyton Agassizii.