^A. Forbesii.^ The common starfish of the Atlantic coast, from Massachusetts Bay to the Gulf of Mexico. This species resembles very closely /A. vulgaris/, but can be distinguished from it by the madreporic plate, which is bright orange, while in the former it has the same color as the animal; also the arms are a little swollen at the base and terminate more bluntly. These two species are very destructive to oyster-beds, especially where their ranges overlap. It is computed that they destroy annually two hundred thousand dollars' worth of oysters. Vast numbers congregate where the feeding-ground is good, and move in long lines from place to place. The oystermen dredge over the beds and bring them up in thousands, then steam them or throw them on the shore above high-water mark. (Plate LIV.) ^A. ochracea.^ The common starfish of the Pacific coast, from Sitka to San Diego. Five rays, each hardly twice as long as the diameter of the body; spines running irregularly over the surface, but forming a pentagon at the middle of the disk and inclosing the madreporic plate; diameter eight inches. It is very common near San Francisco on rocks at low-water mark. (Plate LIV.) ^A. gigantea.^ Body very large and swollen; six rays, somewhat less in length than twice the diameter of the disk; aboral surface covered with numerous short, blunt, equidistant spines of uniform size and regularly distributed; spines contracted at the base and striated; diameter two feet. Found on the California coast. [Illustration: PLATE LIV. Cribrella sanguinolenta. Heliaster multiradiata. Asterias Forbesii. Asterias ochracea.] TABLE SHOWING THE CLASSIFICATION OF THE BRITTLE-STARS DESCRIBED IN THIS CHAPTER. Class =OPHIUROIDEA= (/Brittle-stars/) Order =EURYALIDA= (/Skin without plates; arms simple or branched, and capable of being rolled up/) Genera Species ^Astrophyton^ ^A. Agassizii^ Order =OPHIURIDA= (/Skin with plates/) ^Ophiopholis^ ^O. aculeata^ ^Amphiura^ ^A. squamata^ ^Ophiocoma^ ^O. riisei^ ^O. æthiops^ ^O. Alexandri^ ^Ophiothrix^ ^O. angulata^ [pg214] CLASS =OPHIUROIDEA= BRITTLE-STARS