STABFISHES OF THE PHILIPPINE SEAS. 229 



breadth of ray at midinterbrachium, 22 mm.; at imier limit of the 

 single row of abactinal plates (distal margin of fourth superomar- 

 ginal plate) 12.5 mm., or length of first (3.3 superomarginals meas- 

 ured on ambitus (varies to 5) ; general form as in ctenipes, but rays 

 a little slenderer; abactinal plates with 15 to 25 central and 25 to 30 

 peripheral granules, which are slenderer on the papular areas ; distal 

 carinal plates of disk with upward of 40 central and 35 to 45 pe- 

 ripheral granules; inferomarginal plates with proximally G to 10 

 appressed sharp spinules, reduced to 3 or 4 at middle of ray, then 2, 

 a single spinule persisting to near end of ray ; furrow spines 7 or 8, 

 continued along the transverse margins as smaller interlocking 

 spinelets; subambulacral spines prominent, slender, tapering, sharp, 

 proximally 2, distally 1; in small specimens 1 throughout. 



Description. — P. ctenipes was described from a comparatively 

 small specimen (R 48 mm.). A comparison of an equal-sized ex- 

 ample of hypacanthus with Sladen's figure of P. cte7iipes (1889, pi. 

 51, ligs. 5 and 6) shows that the latter is of stouter build with slightly 

 broader superomarginal plates, especially interbrachially. The 

 abactinal area circumscribed by the marginal plates is arcuate pen- 

 tagonal, the amount of indentation being variable, but slight. 

 Abactinal plates with more numerous granules than in ctenipes. A 

 median radial j)late about halfway from the primary radial to base 

 of ray has about 25 to 30 peripheral and 15 to 25 central granules, 

 much the same shape as in ctenipes, but on the radial papular area 

 the marginal granules are much slenderer than the central. On the 

 center of disk and a narrow interradial area the marginal granules 

 are as in Sladen's figure (pi. 53, fig. 1). The number of granules 

 increases from the primary radial to the rectangular plates separat- 

 ing the superomarginals and then gradually decreases along the ray. 

 The 2 or 3 plates preceding the rectangular carinals have 35 to 45 

 rather slender peripheral granules and upward of 40 larger round, 

 truncate, spaced ones. In medium-sized and relatively small speci- 

 mens the number is not greatly reduced. A specimen from station 

 5420, about the size of Sladen's type of ctenipes, has 23 central and 

 28 peripheral granules on a primary radial plate. The lateral plates 

 decrease gradually in size toward the margin, and those of the cen- 

 ter of disk are a trifle smaller than the radial plates. All the 

 abactinal plates are distinctly tabulate, although the tabulum is low. 



Papulae absent from the ray, center of disk, and a narrow inter- 

 radial band; present, in sixes about each plate, forming a broadly 

 oval radial area, reaching nearlj' to interbrachial septum. Plates of 

 papular areas with 6 short lobes by which they touch, the lobes 

 decreasing in size as the distal carinal plates of the disk broaden. 

 The other plates of disk are roundish or slightly hexagonal and 

 closely fitted together; those of the ray are rectangular. 

 13434— Bull. 100—19 16 



