WEST INDIAN STARFISHES 157 



acute. Disk rather wide; paxillar area at base of rays wide, 

 about four times as wide as the narrow marginal plates; the 

 paxillae are small and even, regularly arranged in transverse 

 rows on rays; their spinules are clavate or capitate. Infero- 

 marginals scarcely project beyond upper ones laterally; their 

 marginal spines long and acute. Inner adambulacral spines 

 long, rather slender; two in second row very unequal; aboral 

 one notably large and stout, not flat, subacute or obtuse. 



A. braziliensis M. and Tros. 



BB, Superomarginal plates in adults are destitute of mar- 

 ginal spines or tubercles. 



G. Superomarginal plates in adult are unusually numerous, 

 (46-48) much higher than long, large, rectangular, evenly round- 

 ed, vertically, compactly granulated, separated by narrow fas- 

 ciolated grooves; proximal pairs larger, more convex. Paxillar 

 area wide, proximally about three times as wide as marginal 

 plate. Paxillge small and even, coronate, crowded, not in obvious 

 rows; their spinules are short, capitate numerous. Inferomar- 

 ginal plates do not project laterally beyond upper ones ; margin- 

 al spines are large, mostly acute. Adambulacral spines are num- 

 erous, nearly all flat, often forming four rows of about three 

 each ; three in second row are flat and truncate ; two aboral lit- 

 tle larger, subequal. A. comptus, sp. nov. 



GG. Superomarginal plates not unusually numerous, usually 

 less than 25 ; large, encroaching on the upper surface. 



H. Superomarginal plates not unusually broad, about 25 to 

 30, granulated, not more than about half as wide as the paxillar 

 area, proximally ; fasciolated grooves wide and deep. Marginal 

 spines of inferomarginals stout and flattened. Adambulacral 

 spines, strong, flattened ; two in second series, truncate, unequal. 



h. Dorsal paxillae do not form obvious transverse rows on the 

 rays; their spinules are subequal, short, capitate or granule-like. 



A. articulatus dubiiis (Gray). 



hh. Dorsal paxillge form regular transverse rows on the rays ; 

 their spinules are numerous and unequal, the central ones larger, 

 so that the outlines of the paxillae are defined. 



A. richardi Perrier. 



HH. Superomarginal plates about 19, large, unusually broad, 

 the breadth exceeding the length ; proximally about as wide as 



