130 NATURAL HISTORY BULLETIN 



These details are now given because this was the first species 

 of the family to be described from the West Indian fauna, and 

 because, owing to its marked immaturity, its identification, from 

 the imperfect description, is difficult. Moreover, there has been 

 a question as to its generic place, since Ludwig has referred it to 

 Pectinaster and has made it the young of my Pontaster sepitus 

 (1885) 1895.* Both these conclusions are erroneous. 



In 1884, Perrier only added that only two interactinal plates 

 separated the inferomarginals from the jaws (a feature of the 

 young) ; that these plates have pectinate pedicellariae ; that the 

 dorsal paxillae have a central caducous spinule ; that the ambu- 

 lacra! feet have small suckers; that the number of marginal 

 plates varies from fifteen to nineteen; that the dorsal marginal 

 spines have a number of spinules around their base ; and that in 

 the larger specimens some pretty long spines surround the cen- 

 ter of the disk. 



Most of these features are common to several other species, 

 especially when young. The last two are of most importance, 

 though other related species have spines on the disk. 



The most distinctive character given is the presence of nu- 

 merous secondary spines around both series of larger marginals. 



In 1894 he referred the species to Cheiraster, although he 

 recognized Pontaster and Pectinaster^^ as distinct genera; and 

 stated that it is nearly related to C. mirahilis but may be dis- 

 tinguished by its shorter rays, broader at base ; its circular pec- 

 tinate pedicellariae; its larger inferomarginal spines, accom- 

 panied by several spines of smaller size ; and by the larger size 

 of the dorsal paxillae. He adds that the interactinal plates are 

 two to six in a single range (a youthful character). 



In neither place does he describe the correct arrangement of 

 the papulae, which would be the only character by which it could 

 be distinguished from Pectinaster. This we can now supply by 



* Archaster sepitus Verrill, Ainer. Jour. Sci., vol. xxix, p. 151, Feb., 1885; 

 Expl. by the Albatross in 1883, pp. 519, 543, 1885. Pontaster sepitus Verrill, 

 Proc. Nat. Mus., vol. xvii, p. 347, 1894; ditto, vol. xlix, p. 137, 1895. 

 Range, 368 to 858 fathoms. Taken at several stations between N. lat. 41° 

 53' and 39° 40'. 



23 Ludwig (1910) referred this species to Pectinaster. Perhaps he was 

 misled by Perrier 's imperfect description of the papular areas. Perrier 

 apparently saw but one lunb of the V-shaped group. 



