WEST INDIAN STARFISHES 195 



plates (as he does in the case of A. articulatus, where they are 

 very small), it is to be presumed that there were none. The 

 existence of four peculiar, appressed, flat spines, presumably on 

 the inferomarginal plates, is the most important character given. 

 He does not say that any are marginal. 



The locality. Cape May, southern New Jersey, is north of the 

 usual range of A. articulatus, and every other littoral species of 

 the genus, known on our coast, but A. americanus occurs farther 

 north, in deep water, off the coast. The latter, however, does not 

 agree at all with the description. 



It is possible that this specimen was not really obtained at Cape 

 May, or if so, that it may have been fished up from deep water, 

 off that shore, by local fishermen. 



It is possible, though not probable, that it was only a very large 

 specimen of a variety of A. articulatus, which is a very variable 

 species, and not infrequently lacks spines on the upper marginals. 



Genus Plutonaster Sladen. 



Pluionaster Sladen, Narrative Challenger Exped., vol. i, p. 610, 1885; op. 

 cit., p. 81, 1889. Perrier, Exped. Trav. et Talisman, pp. 312-313. 



Form is stellate with a broad flat disk and rapidly tapered, 

 rather rigid rays. The marginal plates are large and thick, 

 rather rectangular, encroaching on the upper side to form a stout 

 border, and standing opposite the lower ones. 



The marginal plates of both series are closely covered with 

 elongated granules. They may bear short, thick spines on one 

 or both series, or spines may be entirely lacking. Grooves are 

 fasciolated. The dorsal area is wide and closely covered with 

 small parapaxillse, showing no median radial row, but often in 

 transverse rows on the rays. 



Papulas are widely distributed, except on the interradial areas. 

 Pedicellariae are generally absent, when present papilliform, with 

 three or four valves. They occur on the interactinal plates. 

 Dorsal pore distinct. 



Adambulacral plates have a regular marginal row of small 

 spines, and on the actinal face two or more longitudinal rows of 

 mostly short or almost granule-like spinules; sometimes one is 

 spiniform. The interactinal plates are numerous and stand in 

 regular rows, from the adambulacral to the inferomarginal plates. 



