5Ò0 



bb. Papulae extending only '/y length of ray; dorsolateral 

 musclebands conspicuous ; marginal mouth spines 5 or 6 

 graduated toward inner tooth . . . A. intermedius new species. 



Acaidltarchaster aciculosus new species. 



Rays 5 (very rarely 6). E, 146 mm; r 16 mm; R 9 r. Width of ray 

 at base, 1Ü mm. Cotype: R 217 mm; r 16 mm; R 13,5 r. Width of 

 ray at base 19 mm. Rays very long, slender, flexible, and tapering 

 gradually from narrow base to attenuate extremity. Abactinal surface 

 covered with stellate plates of 2 general sizes, large primary plates 

 bearing a raised tabulum with a central, long, slender, movable, needle- 

 like spine surrounded by a circle of 8 to 15, divergent very slender, seta- 

 like spinules '/s to over Y2 ^^^ length of spine; interspersed among these, 

 smaller plates with spinules only, or perhaps an incipient central spine; 

 beyond middle of ray, plates with a uniform covering of minute spinelets, 

 3 or 4 to a plate; a few abactinal pectinate pedicellariae. Papulae 

 numerous, large, distributed all over disk and on ray to about ^, 3 R from 

 center. Superomarginals with 2 or 3 long slender movable spines, 

 surrounded by 7 to 12 auxiliary spinules, inferomarginals similarly 

 armed. About 3 or 4 (as few as 1, or rarely all 5) interradii with an odd 

 marginal plate, in both series, bearing 1 or 2 spines, but not always 

 corresponding; an odd superomarginal sometimes opposite paired inter- 

 radial inferomarginals. Adambulacral plates with 2 to 4 furrow spinules, 

 and 2 or 3 long slender actinal ones in oblique series. Mouth plates 

 broadly spade-shaped with 9 to 15 marginal spinules, subequal except for 

 the inner 1 or 2 which are enlarged to form teeth. Typically, no actinal 

 pedicellariae; exceptionally these may be present in northern examples. 



Between San Diego and San Clemente Island, Cal., 542 fathoms. 

 Bottom, green mud. 



Acantharchaster variabilis new species. 



Nearly related to A. aciculosus, but differs in having a firmer 

 abactinal integument with closer fitting plates; in the reduction of the 

 spinules surrounding abactinal primary spines, these being either very 

 short, or when lengthened comparatively few, and not forming a dense 

 chevaux-de-frise; in having short accessory marginal spinules; in having, 

 as a rule, 4 to 6 (instead of 1 to 3) furrow spinules. R 175 mm: r 15 mm; 

 R 11,6 r. Breadth of ray at base 19 mm. 



Bering Sea, north of Unalaska, 350 fathoms. Bottom, mud. 



Acantharchaster variabilis pedicellaris new subspecies. 

 Resembling A. variabilis, but differing in having a large number of 

 abactinal pectinate pedicellariae which are scattered all along ray; in 



