WEST INDIAN STARFISHES 191 



correspond to the fii'st pair of inferomarginals. The ambulaeral 

 feet are conical, subacute. 



The jaw-plates are prominent, convex, but not much enlarged, 

 covered with acute spinules, the apical ones stouter. 



The adoral series of spines are not deeply depressed into the 

 groove, as they are in some of the allied genera. 



The pedicellariae are small and papilliform or conical. The 

 largest are on the interactinal plates. (See pi. xiii, fig. Ic.) 

 They have four to six small, slender, convergent valves. Those 

 on the dorsal and marginal plates are considerably smaller with 

 three or four valves. They sometimes occur, also, on the adam- 

 bulacral plates. 



For some additional details see the description and photo- 

 graphic plates by Fisher (op. cit., 1911). 



Perrier (op. cit., 1904) united this genus to Leptychaster 

 unnecessarily. 



The two original specimens were from the Blake Exped., sta- 

 tion 25, in 92 fathoms, off Grenada ; and in 175 fathoms, off Ha- 

 vana. 



The Bahama Expedition took it at sta. 58, in about 200 fath- 

 oms, off Florida (4 specimens), and sta. 64, in 110 fathoms, oft' 

 American Shoal (4 specimens). 



It was dredged by the Albatross at several stations in the West 

 Indies, in 92 to 175 fathoms, and in the Gulf of Mexico, off Ala- 

 bama, in 178 fathoms, station 2357. 



Genus Sideriaster Yerrill. 



Sideriaster Verrill, Eevision Genera, p. 219, 1899. Type, S. grandis Ver. 



Form broadly stellate with a very large disk; dorsal surface 

 convex, and capable of inflation, closely covered with uniform, 

 stellate paxillge. Upper marginal plates are not large, lateral in 

 position. Interactinal areas large, with numerous plates, mostly 

 in single radial rows, with fasciolated grooves between. 



The dorsal paxillae are large, closely arranged, and nearly uni- 

 form in size and shape, regularly stellate, with short, even spin- 

 ules. 



The madreporic plate is very large, round, flat, fully exposed, 

 and has very numerous, thin, radiating gyri. 



