ASTEROIDEA OF NORTH PACliH. ,\M> AD.JAi KNT WATERj — FISIIEH. 317 



(but in a variety are closer) and usually arc not visible from above, on inner lialf of 

 ray. They do not extend inwanl from the margin any great tiistante on the inter- 

 brachial arcs, being there smaller and closer together. They dilTer from the mar- 

 ginals of borealis in having much more numerous and shorter spinelets, in having 

 a relatively higher pedicel, with a more evenly semicircular edge and much more 

 contracted base, in not forming a conspicuous marginal fringe as in borealis, and in 

 being more numerous and ch)ser together. They differ from those of dmvsoni in 

 being higher, witli a more convex or semicircular edge, and in being more widely 

 spaced. 



Adambulacral platesof (lie same general type as in dawsoni. Kurrow spines long, 

 at base of ray three or four, then three (the adoral becoming shorter and shorter), 

 then two, antl fiiially, near the end of ray, only one. The spines are slender and 

 webbed at the base, the outer part having a flange of tissue, and the middle spine is 

 loijgest, about as long as the distance between the inner end of two adjacent actinal 

 series. Subambulacral spines (proximally five to eigiit, distally five, four, or three) 

 longer, tapering, pomted, similarly webbed and membrane-sheathed, in a transverse 

 series the inner end of which bends aborally so that the inner spine is opposite the 

 aboral furrow spme while the outermost is at the adoral edge of plate. These 

 spines are slenderer than in borealis, stand on a ridge of the plate and are subequal in 

 length, or the outermost shortest, and in length about equal the base line of the 

 series, or the distance between the inner end of three adjacent actinal series or 

 slightly more than the combined length of two adambulacral plates. The maximum 

 number of spines in the largest specimen is six; in a smaller example, eight. In 

 dawsoni the actinal comb is straight, not curved, as in this species. 



Mouth plates similar in form to those of borealis, with eight to eleven marginal, 

 and upward of fifteen suboral spines on each. The former increase very markedly 

 in length at inner angle, the inner three or four being long, the innermost as long as 

 the intcrradial diameter of combmcd plates. The suborals usually form a crowded 

 series with those of the companion plate, the mnermost being nearly as long as the 

 teeth, the outer rapidly shortening or forming two or three series parallel to suture. 



Actinal intcrradial areas larger than in borealis and much larger than in dawsoni. . 

 with spaced low pseudopaxilhe in chevrons, bearing a variable number, but usually 

 numerous (as few as five, as many as fifteen) slender spinelets united at the base by 

 membrane. A single scries of small intermediat(> plates bearing one to few spinelets 

 extends over half the length of ray. 



Madreporic body halfway between margin and center of disk, surrounded and 

 partly obscured by five to eiglit large paxilhr. 



Variations. — The specimens from stations 479J, 47S4, 28.1.3, and 3223 constitute 

 a well-marked variety with eight rays. The number is usually nine (station 3331). 

 less often ten; specimens from 3.500 are cither eight-, nine-, or ten-rayed; the eight- 

 rayed being similar to those from 2S,53 anil 47S4, the others resembling examples 

 from 3331. The eiglit^rayed variety (pi. SO), as compareil to the form from station 

 3331 (pi. 87), has broader rays, more compactly placed pa.vilhe, with more numer- 

 ous spinelets and larger sui>eromarginal paxilhr, which usually stand above the 

 inferomarginals rather than oj)posite the interval between. The inferomarginals 



