WEST INDIAN STARFISHES 99 



which is confined to the Indo-Pacific ocean, and several other 

 Pacific genera. 



Genus Oreaster Miiller and Troschel. 



Pentaceros Linck, De Stellis Marinis, p. 21, 1733 (not binomial). Schiilze, 



Betracht. der Verstein. Seesterne, p. 50, 1760, t. Sladen (not binomial). 



Schroter, Mus. Gottwald. Testae. Stell. mar., etc., p. 58, Niirnberg, 1782, 



t. Sladen (not binomial). 

 Pentaceros Gray, Ann. and Mag. Nat. Hist., vi, p. 276, 1840. Synopsis, p. 



6, 1866. Perrier, Revis. Stell., v, p. 52 [236], 1876. Agassiz, A., 



North Amer. Starfishes, p. 108, pi. xvi, figs. 1-7 (structure), 1877. 



Viguier, Archiv. Zool. Exper. et Gen., vii, p. 193, pi. xi, figs. 4-6, pi. 



xii, figs. 3, 4, 8-11 (structure), 1878. Sladen, Voy. Chall., xxx, p. 343, 



1889. Perrier, Exp. Trav. et Talism., p. 406, 1894. 

 Goniaster (pars) L. Agassiz, Prodr., p. 191, 1835. 

 Oreaster Miill. and Troschel, Syst. der Aster., p. 44, 1842. Von Martens, 



Ostasiat. Echinod., p. 81, 1866. Liitken, Vidensk. Meddel., 1859, p. 

 63; op. cit., 1864, p. 161 [39]. Verrill, Trans. Conn. Acad. Sci., i, 



pp. 278, 343, 1867 ; op. cit., p. 367, 1868. Perrier, Pedicellaires, p. 69, 



1869. 



This genus includes many large, massive, tropical starfishes, 

 with a large and usually high, swollen, angular disk and rather 

 rigid-looking rays. 



The dorsal plates are thick, stellate-reticulated, leaving large 

 papular areas between them, with many small papulae. The 

 plates are always granulated and some or all often bear large 

 spines or tubercles. 



The marginal plates are paired, but not very large, and partly 

 concealed by the thick granulose dermis. The inferomarginals 

 are often confined to the lower side, the superomarginals form- 

 ing the border. Those of each series may bear stout conical 

 spines or tubercles. 



The interactinal plates are numerous on the disk and are usual- 

 ly closely tesselated, bearing granules and conical spines. Strong 

 internal interradial septa containing large calcareous plates sup- 

 port the disk. 



The adambulacral plates bear, each, a longitudinal row of two 

 to four or more rather small spines on the inner margin and one 

 or several much larger and thicker spines on the actinal surface. 



Pedicellariae are often numerous, bivalve, usually small, or 

 about equal to the granules among which they are scattered. 



