1887.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 445 



scribed. In the latter the same general arrangement of the spines is 

 apparent, but it is sometimes much less marked. On the free portions 

 of the rays, especially in young specimens, the single spines of the me- 

 dian rows are often replaced by clusters of two to four small spines of 

 the same general shape, closely placed. The color of the spines is dingy 

 or yellowish white ; of the abactiual surface, a bluish black, tlie latter 

 color extendiug over the bases of the spines. • The contrast between the 

 spines and surface is, therefore, very striking, especially in alcoholic 

 specimens. 



The adambulacral spines form a single row of closely placed, regu- 

 larly alternating, large and small spines (one to a plate), as in H. mi- 

 crobrachia, the latter being limited to the outer half of the grooves. The 

 larger spines vary greatly in size and shape in the different specimens. 

 In the largest specimens they are long and stout, rounded, subcyliu- 

 drical, and neatly convex at the tips, which are sometimes slightly en- 

 larged. Toward tlie actinostome they become slender and acute, and 

 at the ends of the rays are very smajl. In another large specimen they 

 arQ much smaller, somewhat more distantly iilaced, tapering, and sub- 

 acute. This is also their usual character in the small specimens. Be- 

 tween the adambulacral and dorsal spines there are from three to four 

 rows of spines, becoming reduced to two rows near the ends of the rays 

 These spiues are mostly larger than those of the adambulacral series 

 nearest to them, taper more or less, and are often slightly flattened. 

 The lowest row follows closely after the adambulacral row, and the 

 spines composing it are often smaller and more like the adambulacral 

 than those higher up on the sides. The general appearance of the ac- 

 tinal surface is very much like that of some of the specimens of H. mi- 

 crobrachia. 



Associated in the same collection with the specimens above described, 

 is a single specimen (15524) which agrees more or less with the Cumimjii 

 in its general characters, but in the size, number, and arrangement of 

 the spines, has more the appearance of H. microbracliia, and suggests 

 the possible identity of those two species. By some it might be regarded 

 as a new species. The longest radius is 72 '""^ ; the diameter of the 

 disk, about 40°^"^ ; entire length of rays, about 50'^°i ; length of free por- 

 tions of rays, about 16"""^ ; number of rays, 34. The spiues are small, 

 about as in microbracliia, but more regular, slightly tapering, rounded 

 at the tips. They are very numerous, bat less so than in microbracliia, 

 and form a more or less regular, simple row on each side of the ray, 

 between which they are distributed much as in microbracliia. On 

 some parts of the surface, especially on the median part of the disk and 

 the outer portions of the rays, they are short and globular in appear- 

 ance, as in the young of Gumingii. 



Professor Verrill {loc, cit, p. 291) refers to ReUaster Cumingii of 

 Gray, several specimens of a short-rayed ReUaster from Zorrites and 

 Paita, Peru. These agree with the specimens above described in the 



