STARFISHES OF THE PHILTPPIXE SEAS. 489 



mediate spines with 1 to 5 papulae to an area extending about half 

 the length of ray. 



The integument is marked by fine channels, somewhat irregular, 

 extending from the carinal plates to the inferomarginals. There are 

 usually 2 of these lines between the superomarginal spines. 



Adambulacral spines 2, slender, flattened, slightly tapered, and 

 truncate. The inner is a little shorter than the outer, which is equal 

 to about the length of 4 plates. On the furrow face of about every 

 other plate, or sometimes on that of several consecutive plates, is a 

 fair-sized, pointed, lanceolate, forficiform, pedunculate pedicellaria. 



Each mouth plate with 2 spines at the inner actinostomial end : a 

 short one, with 2 pedicellariae at the base, directed across mouth of 

 furrow, and the second, over twice as long and much heavier, flat- 

 tened and truncate, directed, w^ith its near neighbor of the other 

 plate, over the mouth. At the outer end of each plate an upright, 

 flattened, sometimes subspatulate suboral nearly or quite as long- 

 as the longer apical spines. 



Type.— C^t. No. 37032, U.S.N.M. 



Tyye-localiUj. — Station 5417, between Cebu and Bohol, 165 fath- 

 oms, gi'ay mud and sand, bottom temperature 54.4° F. ; 1 specimen. 



Distribution. — Known onl}^ from near type-locality, 88 to 165 

 fathoms. 



SpecimeTis examined. — In addition to the type, 1 from station 

 5415, between Cebu and Bohol (near type-locality), 88 fathoms, fine 

 sand, bottom temperature 62.4° F. 



Remarks. — This species closely resembles D. eustyla (Sladen), 

 which is known only from the vicinity of Tristan da Cunha. Both 

 species have a single series of actinal intermediate spines, but in 

 eustyla, judging from Sladen's figure, the series extends practically 

 to the tip of the ray. Sladen mentions these as a third inferomargi- 

 nal spine, but they seem to belong rather to actinal intermediate 

 plates. In hypacantha the inferomarginal spines are more spaced 

 from the adambulacral spines, the major pedicellariae are much more 

 numerous, and are present on the actinal surface, as well as in the 

 furrow, the rays are longer. D. dubia Clark, from Botany Bay, 

 has shorter, relatively stouter rays, stouter abactinal skeleton, larger 

 major pedicellariae, broader and more flattened outer inferomarginal 

 spines, deeply furrowed on the actinal side. I). mazopJwra (Alcock), 

 D. euplecta Fisher, and D. mollis Hutton lack the actinal intermedi- 

 ate spines of hypacantha. In D. euplecta the inferomarginal spines 

 are closer to the furrow spines than in hypacantha, the actinal inter- 

 mediate plates being smaller and more tightly wedged between the 

 adambulacrals and inferomarmnals. 



