STAEFISHES OF THE PHILIPPINE SEAS. 323 



quite short. On the actinal surface in an oblique transverse series 

 are usually 2, sometimes 3. large, tapering, pointed thorny or rough- 

 ened spines, the longest 4.5 mm, and longer than the actinal inter- 

 mediate spines. When there are 2, the spines are nearly equal and 

 about as long as 2 plates. When there are 3, 1 is shorter, and instead 

 of forming a straight series they stand often in a group. One plate 

 has 4 spines. Most of the plates of the proximal two-thirds of ray 

 bear an upright, entrenched pedicellaria with 2 or 3 subspatulate, 

 often unequal, spiniform jaws, rather larger than the actinal inter- 

 mediate pedicellariae, and situated usually just adorad of the inner 

 subambulacral spine. The plate is bordered by convex granules 

 covered by a thin membrane. The inner granule of 'the distal mar- 

 gin is often conical and spiniform. 



Mouth plates triangular, the margin adjacent to first adambulacral 

 slightly concave and about as long as that bordering the furrow. 

 Marginal spines 15, all but the 2 innermost similar to the furrow 

 spinelets. The innermost spine is abruptly enlarged, heavy, sub- 

 prismatic, bluntly pointed; sometimes the second spine is slightly 

 enlarged. In the middle of the actinal surface is a tapering, sharp, 

 smooth, or slightly roughened suboral spine, or 2 such spines (5 plates 

 having 1 and 5 plates, 2). A rather irregular series of convex gran- 

 ules, larger than those bordering the adambulacrals, follows the 

 outer and mesial margins of plate. 



Madreporic body rather large, situated one-third r from center 

 and traversed by radiating branched ridges separated by fine striae. 



The upper end of each ambulacral ossicle is covered with small 

 spiny projections and the free edge of the plate, between consecutive 

 pairs of ampullae, is thin, serrulate, and bladelike, the serrations 

 being a continuation of the spiny projections of the upper end of the 

 plate. 



Tube-feet with a well-developed sucking disk. 



Color in alcohol, chocolate brown, lighter beneath, the integinnent 

 between the abactinal plates being reddish brown. 



Type.— C^t. No. 30558, U.S.N.M. 



Type-locality.— ^t2ition 5412, between Cebu and Bohol, 162 fath- 

 oms, green mud, bottom temperature 54.8° F. ; 1 specimen. 



Bhtribution. — Known only from the type-locality. 



Remarks. — This genus is virtually CalUaster with swollen or en- 

 larged terminal superomarginal plates and thorny or roughened 

 spines. The last character suggests Milteliphaster Alcock, which 

 has the actinal spines ending in swollen bifid or multifid points. The 

 structure of the actinal spines is apparently the only character which 

 separates Milteliphaster from CalUaster. In Astrothauma the 

 roughened spines resemble those of certain cidaroids. The fact that 

 the swollen terminal superomarginal may bo replaced by 2 or 3 



