442 BULLETiisr 100, united states national museum. 



Distribution. — Bed Sea to the JPhilippine and Ryukyu Islands, 

 Molucca Islands, Viti, Fiji, and Samoan Islands. 



Specimens examined. — Four : 



Pangasinan Island, vicinity of Jolo, coral reef ; 1 specimen. 



Little Santa Cruz Island, vicinity Zamboanga, reefs; 1 specimen. 



Cataingan Bay, Masbate, coral reefs ; 1 specimen. 



Lode Bay, Destacado Island, between Samar and Masbate, rocks 

 and coral ; 1 specimen. 



ACANTHASTER BREVISPINUS Fisher. 



Plate 117 ; plate 118, fig. 1 ; plate 131, figs. 6, Qor-d. 

 Acanthaster hrevispmus Fishee, 1917&, p. 92. 



Diagnosis. — Resembling A. mauritiensis de Loriol, but differing in 

 having the abactinal spines of disk reduced to mere spinelets, in 

 having smooth or nearly smooth disk spines on both surfaces, and 

 in having only 2 or 3 furrow spinelets, shorter than the length of 

 their plate instead of decidedly longer. Rays 14 to 16. R=90 mm., 

 r=51 mm.; R=:1.7G r. 



Desc7^iption. — Abactinal surface of disk beset with numerous, 

 slightly tapered, skin-covered spinelets, 2 mm. or less in length. 

 They frequently end in a slightly expanded three-edged, pointed 

 tip. Most of the spinelet is smooth, but a few granules are found 

 around the base of the spinelet proper and sometimes for a third of 

 its length. On some of the spinelets the granules, which are hidden 

 by membrane until dried, mount up one side nearly to the expanded 

 tip. The spines of the rays are more widely spaced and vary from 

 5 to 10 mm. in length. They increase in size toward the end of the 

 ray and have a sparse fine granulation usually hidden by skin. In 

 A. planci the spines are articulated to an elevated tabulum or column, 

 but in this form the column is almost wanting. 



The abactinal spines are more numerous and much closer to- 

 gether on the disk than in A. planci., as the abactinal skeleton has a 

 closer mesh. Granulation of abactinal surface spaced and fine on 

 disk, increasing in coarseness and density toward the margin. 

 Abactinal pedicellariae small, two- or three- jawed, and 0.5 to 0.75 

 mm. high. The jaws are thick, round-tipped, and the whole pedicel- 

 laria may be nearly as broad as high. In A. planci the abactinal 

 pedicellariae are very slender, the jaws being 3 to 6 times longer 

 than the width. 



Furrow spinelets 2 or 3, occasionally 1, short, unequal, tapered, 

 the longest generally a little shorter than its i^late. When there 

 are 3 the median is the longest. In the furrow, abactinad to the 

 adoral furrow spinelet is a prominent two- jawed pedicellaria and 

 about the same length as an average furrow spine. Its jaws are 

 oriented dorsal and ventral. The subambulacral spines are about as 



