528 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Remarks. — This species has more numerous rays than any of the 



4 species described by Alcock, none of which have isolated spinelets 



on the disk, nor a similar adambulacral armature formula, with 2 



furrow spinelets adorally. Craterohrisinga evermanni Fisher of 



the Hawaiian Islands resembles the present species but differs in hav- 



1 ^ J, • 1 .A 1 'i + -?+^ o + ^+/\ 

 mg 15 rays, no adoral furrow spinelet( formula ^ — or ^ I 



very much slenderer and shorter suboral spines which are not bent 

 at the base; only a rudimentary aboral marginal mouth spinelet, or 

 none. The superficial appearance of the rays is very similar, but 

 the ray of moluccana is more depressed and relatively broader than 

 is usual in ever7nanni. The condition of the gonads and first few 

 subambulacral spines is quite different in the 2 species, as their 

 generic position indicates. 



ASTROSTEPHANE ACANTHOGENYS Fisher. 



Plate 148, figs. 1-3 ; plate 153, figs. 1, la-d. 



Brisinga acanthogenys Fishee, 1916&, p. 33. 

 Astrostephane acanthogenys Fisher, 1917/, p. 421. 



Diagnosis. — Eays 11. Costae 20, complete, prominent, well-spaced, 



vvdth 1 complete and 1 or 2 incomplete bands of intercostal pedi- 



cellariae; costal spinelets fairly prominent, few in number; disk 



small, with beveled margin ; plates granulif orm, spaced, with usually 



2 or 3 very small spinelets, but no pedicellaviae; lateral spines long, 



equaling length of 7 or 8 adambulacral plates; no integumentary 



prickles on rays; adambulacral plates about as wide as long proxi- 



i + I 

 mally; armature proximally ^X7' mouth plates with 2 suboral 



spines. Breadth of disk=3i times width of ray at base (6 mm.), 

 actinostome=2^ times same; height of disk^three-fourths breadth 

 of ray at base. R=350 mm. (complete ray), r=ll mm. 



Description. — Disk small, the abactinal surface scarcely at all 

 raised above abactinal surface of ray; margin beveled. The tiny 

 granuliform platelets bear 1 to 3 extremely small, delicate, and sharp 

 spinelets, which by reason of their membranous sheaths appear to 

 be rather robust, tapering, and pointed. In the central part of the 

 disk they are 0.25 to 0.3 mm. long, decreasing gradually toward the 

 border, and are spaced about one-half to their own length; pedicel- 

 lariae seem to be lacking. 



Costal region swollen, occupying not quite one-third length of ray. 

 Costae 20, complete as a rule, except in the case of the first 2 or 3 ; 

 well spaced, prominent, fairly straight, and armed rather sparsely 

 with sharp conical spinelets, about half as high as the ridge. The 

 ridges are spaced a distance equal to three-fourths to once the width 



