274 Verrill, Notes on Radiata. 



may be the more mature condition of this species. It agrees in most 

 of the characters, excejjt in having small tubei*cles on all the upper 

 marginal plates and in the character of the spines of the lower sur 

 face. In form and the peculiar character of the marginal spines, it 

 agrees very closely. This specimen was considerably larger (radii of 

 rays 49"'"' ; of disk 17'") and came from Costa Rica. 



Gray's original descri})tion of this species,* which, though very 

 brief, agrees, quite well with our specimens, is as follows : " Upper 

 plates spineless, lower produced." " Rays one-fourth longer than 

 the diameter of the body, broad, tapering ; spines broad, stout, 

 depressed." " Like A. marginatus, but the arms are shorter and 

 broader." San Bias, — Mr. Cuming. 



Astropecten Orstedii Liitken, Vidensk. Meddelelser, 1859. 



Rays moderately long, rather broad at base, tapering regularly to 

 the acute ends. Greatest to least radii as 5 : 1. A specimen measur- 

 ing 3 inches from the center to the end of the rays has 36 marginal 

 plates. Interambulacral plates each with an inner row of three slen- 

 der spines, of which the central is a little longer than the others, and 

 outside of these a single, large, blunt spine, which is somewhat 

 flattened, and nearly twice as long as the inner ones. Exterior to these 

 the same plates bear several slender, short spines. Lower marginal 

 plates broad, projecting a little beyond the upper, closely covered 

 with short, blunt, spicula-like spines, and bearing a transverse series 

 of five or six strong, sharp spines, which bend somewhat toward the 

 tip of the ray. The first of these spines are of about the same length 

 as the larger interambulacral, toward the margin of the ray they in- 

 crease in length, the longest being -35 of an inch long and very strong 

 and sharp. The uppermost row is irregular and the spines smaller. 

 The upper marginal plates are narrow and high, the two basal ones 

 of each ray bearing a large, conical, sharp spine, '2 inch or more 

 long ; all the others, two subequal, smaller spines, of the same shape, 

 which form two regular rows. Central region of the rays covered 

 with paxillae, which are longer and less crowded than in most spe- 

 cies. Around the center of the disk some of the paxillse have a cen- 



* This species may be at once distinguished from the preceding by its broad, short 

 rays, which do not taper to long slender points, by the broader disk and dorsal area of 

 rays, by the stouter spines of the lower plates, which are flattened and rather blunt, 

 instead of round and sharp, and by the even granulation of the lower surface, and 

 much less spinose character, which gives it a smoother appearance. The small tuber- 

 cles of the upper plates, also, are more developed toward the tip of the rays, while in 

 the preceding they appear only at the base. 



