314 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



jMursinal jjlates numerous, separated by their length or less; larger thiin in 

 endeca, the inferomarginals being slightly higher and with fifty or more spinelets, 

 the inferior of wliich are much the longest, and exceeding the height of the pedicel, 

 the others graduated in length toward the upper end of the plate, being there about 

 the same height as on the paxilla\ In shallow- water specimens the pedicel is no 

 higher than in endeca, although certain examples from deeper water (as for instance, 

 station 3460) have liigher marginals and are not typical in respect to the abactinal 

 paxillse which are convex, not flat-topped. Typically the superomarginals are larger 

 than in endeca and are larger than the immediatel}- adjacent abactinal paxillae, 

 having about twenty- peripheral and ten to twelve central spinelets, but the number 

 is variable, hke every other character. Sometimes the superomarginals are directly 

 above the corresponding inferomarginals, but sometimes they alternate, both arrange- 

 ments being found on the same ray. 



Adambulacral spines long and bristling, the furrow series especially being 

 much longer than those of endeca. Furrow spines stout, though slender, tapering, 

 bluntly pointed, skin-covered, united basally by a web, tliree or four in number 

 (on the first adambulacral, five or six). Actinal series straight (occasionally very 

 shghtly curved) containing five or six subequal, tapering, stout, bluntly pointed, 

 or cliisel-tipped spines, the innermost equal to or a httle longer than the furrow 

 spines, the others successively shghtly shorter. The iimermost spine does not stand 

 out of hne and aborad to the rest, nor is the series conspicuously curved as in endeca, 

 except sometimes at base of ray. The straight actinal series will serve to distin- 

 guish this from other closely related forms. These actinal spines, when erect, 

 extend conspicuously beyond the level of the marginal paxillae. 



Mouth plates broader than in endeca, even when the rays of the latter are less 

 numerous. Marginal spines nine to eleven, the outer ones conspicuously longer 

 than in endeca, being subequal to the adambulacral furrow spines (these being 

 short in endeca). The inner four or five are still larger, the innermost equahng 

 or exceeding the interradial dimension of the plates. The actinal surface bears a 

 single or double row or group of five to ten prominent spines, the inner longest; or 

 only one or two spines. There seems to be great variabiUty in this character. 



Actinal interradial areas very small in typical shallow water examples and 

 containing about twenty to twenty-five plates bearing a circle or group of about 

 six to twelve webbed spinelets much longer than those of dorsal paxillae and about 

 equaUng or shghtly exceeding the longest inferomarginal spinelets. The variety 

 from stations 3466 and 3459, having ten and eleven rays, has decidedly larger than 

 typical interradial areas, as has also an eight-rayed specimen from station 4247. 

 In these the number of plates to an area is upward of sixty-five. As scarcely two 

 specimens in the collection are ahke and the variations do not seem to be related 

 to locahty, no varieties have been named. 



Madreporic body conspicuous, midway to margin (or nearer center of disk) 

 and bearing several paxillae near or on its margin; striae irregular. 



Color in hfe, reddish brown above and j^ellow beneath (J. C. Brown, from a 

 specimen taken at Postelsia Point, Renfrew District, Vancouver Island, British 

 Columbia). A specimen from Friday Harbor, Washington, in formalin, is grajnsh 



