S lUI.I.KTlX 76, UNITED STATES national museum 



It is obvious thai Asterias rubens, Asterias vulgaris, and Asterias amurensis are 

 v,i\ olosely related and it is profitless to discuss whether they are distinct species or 

 subspecies. There is qo evidence of geographic intergradation between rubens and 

 dmurt nsi8. 



Diagnosis. Differing from .1. minus Linnaeus in having, when adult, conspic- 

 uously broader rays, more numerous, usually shorter abactinal spinelets; 5 to 10 

 channeled or scoop-shaped supermarginal spines instead of two to five more or less 

 terete, tapered, cylindrical, or clavate ones; in having a more nearly plane actinal 

 surface (sharply defined 1>\ the rather thin edgo of the ray, bearing a cheveux-de- 

 frise of 9uperomarginal spines), and by having a broader, flatter actinal interradial 

 region; intermarginal spines frequently present. Kays constantly five; abactinal 

 surface low -niched, resistant or ilaccid; actinal surface nearly plane, with an unusually 

 broad actinal area on proximal third of ray; rays broad at base tapering rapidly to a 

 blunt point; interbrachia angular; adambulacral spines proxhnally usually three and 

 two alternating; inferomarginal spines usually two. Large specimen, R 195 mm., r 

 5 ■'> mm., R = 3.68 r; breadth of ray at base 65 to 07 mm., or one-third of r. 



Description. This species is very variable. While large specimens all have the 

 same general appearance and are easih- recognized, a detailed analysis of the struc- 

 ture will reveal considerable diversity in the size of the skeletal parts, especially of 

 the dorsum, and in the number, robustness, and form of the spines. The breadth of 

 the ray increases with age in such a way as to alter very materially the appearance 

 of the animals. Quite immature specimens are therefore unlike the adults in general 

 appearance. The following description is based upon a large specimen from station 

 32 12, 1 1 fathoms, Bristol Bay. (PI. 2, fig. 3; pi. 3, fig. 5.) Some of the variations 

 exhibited by adults from southern Bering Sea are also noted. Under variations are 

 listed the principal varieties which are present in a large series of specimens examined. 



The Bristol Bay example measures: R 195 mm., r 53 mm., breadth of the ray 

 at base, 65 to 67 mm., or about one-third R. The actinal surface is low arched, 

 rather stout and resistant, and is beset with numerous uniform, small but robust 

 spinelets 1 to 1.50 mm. long, outlining a very irregular and quite open mesh, con- 

 taining many papulae, some of which are retracted, others inflated. The skin is 

 pulpy and minutely wrinkled. A carinal series is scarcely discernible, though it is 

 well marked in other specimens from the same haul by reason of the spines being 

 much more closely placed. Laterally the spinelets tend to form longitudinal irregu- 

 lar series. The spinelets are about 0.75 mm. thick, often clavate, irregularly truncate 

 with a groove or a shallow pit at the tip. The tip may be compressed and incipiently 

 bifid. The groove may be simply a cleft in the side of the little pit or it may 

 extend down the side of the spine which becomes a thick-walled half-tube. The 

 distal spinelets are mostly without pits or channels. There is a good deal of varia- 

 tion, depending upon age ami locality in the forms of the abactinal spinelets. They 

 tend to become stouter and more gouge-shaped with age. in many small and medium- 

 sized examples the spinelets are slender clavate or robust clavate, blunt or truncate, 

 without any groove. 



The superomarginal plates define the ambitus and their spines, which are about 

 twice as long and two or three times heavier than the dorsolaterals, form a dense 

 cheveux-de-frise on t he very angular margin of the ray. There are six to eight divar- 



