STAR-FISHES. 159 



ulation of flat, irregular, star-shaped plates, from which diverge longer flat pieces 

 connecting the others together ; the plates and their connecting links are all imbri- 

 cated, that is, overlap each other. 



Asterina folium occurs in the West Indies and in Florida. Asterina is a large 

 genus, almost world-wide in its distribution. The skeleton is formed of imbricated 

 or over-lapping and notched ossicula, and this structure is usual in the family, an ex- 

 ception being Disasterina abnormcdis, in which singular species, a native of the coast 

 of New Caledonia, the plates of the back are disjoined, leaving between them mem- 

 branous spaces, most of which are pierced by a tentacle. In the genus Patiria, the 

 plates of the back are rounded, and simply touch each other. P. crassa is from 

 "Western Australia. 



In the GoxiASTERiD^, the skeleton, at least on the lower face, is formed of rounded 

 or polygonal ossicles, forming a kind of pavement, and there are usually two rows of 

 marginal plates of comparatively large size. The body approaches more or less to the 

 pentagonal shape, the arms projecting but slightly, and there are two rows of suckers. 

 Some very fine examples of this family are found upon the west coast of this con- 

 tinent. Prominent among them is Oreaster occidentalis, which measures eight or 

 nine inches across, and is also of considerable thickness in the centre of the disc. It 

 ranges northward to Lower California. 



A very beautiful species, with long, sharp spines upon a bright red disc, is Nido- 

 rellia armata, a pentagonal, cake-like star some five or six inches across. Amphiaster 

 insiffnis, another Lower Californian species, has short, flat arms and a flat disc, and the 

 regular arrangement of its spines and tesselated plates renders it exceedingly beautiful. 

 A more northern species is Mediaster equalis, which has been found as far north as 

 Puget Sound. 



Astrogonium phrygianum is a large, bright-red pentagonal star-fish, which resides 

 at dej)ths of from twenty to fifty fathoms, on rocky bottoms, in the Gulf of Maine and 

 northward. A. granvlare is from Scandinavia. Pentaceros reticulatus is about eight 

 inches across the arms, and is found on both sides of the Atlantic, at the Cape Verde 

 Islands, and in the "West Indies. In Culcita the shape is pentagonal, and the tips of 

 the ambulacra appear on the dorsal surface. The Goniasteridae are more numerous 

 in types than any other, family of star-fishes. Their principal centre of distribution 

 seems to be the west coast of Australia and the Malaysian and Melanesian archi- 

 pelagos. 



The LiNCKiADJi have a skeleton composed of rounded or elliptical ossicles, either 

 contiguous or united by rods. There are no spines, but the surface of the body is 

 smooth or uniformly granular. The species are most numerous in hot regions. 



Linckia unifascialis, a fine species ranging from Lower California to Peru, and 

 Linckia guildingii, of the "West Indies and Florida, are examples of the typical 

 genus. Ophidiaster pyramidalis is a large species with the same range as Z,. wii- 

 fascialis. 



The EcHiNASTERiD^, as defined by Perrier, have a skeleton composed of a network 

 of lengthened ossicles, and have two rows of ambulacral feet. Spines arise from the 

 ossicles of the dorsal surface. 



JEchinaster sentus is a five-armed species, abundant in the "West Indies and 

 Florida, and extending north to New Jersey. The spines are completely sheathed in 

 membrane, and occur only at the angles of the limestone polygons of the dorsal 

 surface. Solaster endeca has eleven or fewer smooth arms, and is widely spread in the 



