412 BULLETIN lOO, UNITED STATES NATIONAL MUSEUM. 



hung and evidently protected by the group of spinelets. In the 

 radial area the slight hollow is on the adcentral border. Inferomar- 

 ginal plates with a conspicuous tapered spine surrounded by smaller 

 spinelets. Actinal intermediate plates with a group (not a comb) 

 of 2 to 4, mostly 3, basally webbed spinelets. Furrow spines usually 

 6, webbed for alDout half their length, the 3 or 4 median conspicuously 

 larger than the laterals ; subambulacral spines usually 4, the 2 median 

 much longer than the laterals (in the cotype there are 5 or 6, of which 

 2 are enlarged). Oral spines 5, webbed, the 2 innermost conspicu- 

 ously enlarged ; suboral spines 3 to 5, upright, webbed, 2 of them of 

 predominant size. Rays 5, rather narrow, longer than usual, and 

 with a rounded extremity. R— 37 mm., r=14.5 nun., R=2.5 r; 

 breadth of ray at base, 15 mm. 



Tyye. — No. 689, Museum of Comparative Zoology, Cambridge, 

 Massachusetts. 



Type-locality. — Ponape, Caroline Islands. 



Distribution. — Caroline Islands. 



Reinarhs. — The number of protuberances probably varies somewhat 

 with age and local conditions. In the cotype, Avhich has R, 25 mm., 

 they are fewer. 



In the Archiv fiir Naturgeschichte (vol. 32, 1866, p. 73), von 

 Martens describes Asterina coronata from Batjan, Molucca Islands, 

 and from Larentuka, Flores Island, and records its occurrence at 

 Amboina. His description states that the relation of the minor to 

 the major radius is as 1 to 2 or 2^, that the abactinal plates are 

 so arranged that the dorsal surface has a honeycombed appearance, 

 the plates bearing 5 or more spinelets, and that scattered over the 

 dorsal surface are groups of 2 to 4 heavy spinelets with a common 

 base, such groups being found on the sides and radial regions of 

 the ray, but not close to the border. On the disk these special spine- 

 lets outline an irregular pentagon. 



The elevated specialized abactinal plates of cristata., with their 

 tuft of enlarged spines, I take to be the same as von Martens's 

 " Biischel von 2-4 starken Stacheln mit gemeinsamer Basis," which 

 he says, " stehen auf den Armen ziemlich zerstreut, sowohl auf 

 dem Riicken als an den Seiten, aber nie ganz nahe am Rande." 

 Thus the chief character of the two species is the same. As Dr. 

 H. L. Clark has suggested in a letter, the two species are probably 

 the same, although there exist certain discrepancies. Von Martens 

 does not mention subambulacral spines, but states that the furrow- 

 spines are "in einer Reihe, 4 oder 5 fast gleich Grosse auf jeder 

 Platte." and that the actinal intermediate plates have 2 relatively 

 long sharp spines. The type of Asterina aetata has 2 to 4, mostly 

 3, actinal intermediate spinelets, usually 6 furrow-spinelets webbed 



