278 Verrill, ISfotes on Eadiata. 



Oreaster occidentalis Vemii, sp. nov. 



A large species, resembling in form and character of the upper sur- 

 face 0. gigas Lxitk. ( 0. retlcidntus M. and Tr.),but less spinose above 

 and not at all so beneath ; marginal plates without spines, or only a 

 few near the ends of the rays. Greater to smaller radii as 2^: 1. 



The largest specimen has a greater radius of 4*3 inches ; smaller 2. 

 Another has the radii respectively 3 "8 and 1*7 inches. Form pentag- 

 onal, with a large, elevated, angular disk, and narrowed, rather slen- 

 der, short rays. The margin between the rays is regularly and deeply 

 incurved, without a distinct angle. The interambulacral plates bear 

 an inner row of slender spines, seven or eight on each plate near the 

 center, and four or five toward the end of the rays, the middle ones 

 longest, the others decreasing in length on each side to the outer ones, 

 which are quite short, thus forming pointed groups. Outside of these 

 there is a second row of much larger, short, flat, blunt spines, three to 

 each plate on the inner and only two on the outer portion of the rays, 

 the middle one, when there are three, being a little the longest and 

 considerably largest, but when there are but two the one nearest the 

 mouth is usually, but not always, largest. The ventral surface is des- 

 titute of spines and covered with coarse, irregular, crowded, unequal 

 granules, among which there are scattered numerous, sessile, two- 

 lipped pedicellariiB, with narrow, elongated openings. In one speci- 

 men the ventral plates, especially near the mouth, have a central group 

 of larger, elevated granules, some of which become twice as high as 

 thick, with a somewhat acute point, thus approaching the character of 

 small spines. On each side of the rays are 18 lower and 17 upper 

 marginal plates in the larger specimen, and one less of each in the 

 smaller. The lower plates belong entirely to the ventral surface and 

 are covered with coarse granules similar to those of ventral plates, 

 becoming finer and more uniform at the outer margin. They all bear 

 numerous small, oblong-oval, sessile pedicellarise, and in the largest 

 specimen are destitute of spines and tiibercles, but in the smaller, 

 from two to four of the plates nearest the end of the rays bear small, 

 stout, obtuse spines or tubercles, which are surrounded at the base by 

 granulations, but naked above. The upper plates, which form the 

 margin, are thick and convex, rather rounded, much longer than those 

 of 0. gig<(S, closely covered with small, angular, convex granules like 

 those of the whole upper surface, among which there are numerous, 

 scattered, sessile, pedicellariae, like those of the lower plates. In the 

 larger specimen none of them bear s})ines, but in the other there are 

 from one to four that bear small, short, stout, blunt, conical spines near 

 the ends of the rays. The upper surface of the arms and disk i 



