STAKFISHES OF THE PHILIPPINE SEAS. 155 



area of small paxillae on the disk. The median radial series of 

 paxillae is not easily distinguishable in nuttingi^ as the radial paxillae 

 generally are smaller than the lateral, and not very regularly ar- 

 ranged. In nuttingi there are over 20 poorly defined longitudinal 

 series, as the paxillae arrange themselves more readilj^ in oblique 

 transverse series. Such an arrangement in oblique series is observ- 

 able in sphaerioflax, in addition to the longitudinal series. Finally, 

 the paxillae of sphaerioplax contain many more granules than those 

 of nuttingi. 



Superomarginal plates 19, enci'oaching conspicuously upon abac- 

 tinal area, rather wide in the interbrachia and decreasing regularly 

 and rapidly in width toward end of ray. The width of the first 

 plate equals the length of 3 measured at the outer end, while at 

 the tip the width only slightly exceeds the length. The plates form 

 a slight bevel, and the rounded upper edge of the ray is near the 

 outer end of the plate. The plates are covered with beadlike gran- 

 ules and a peripheral series of slender spinelets, becoming capillary 

 in the deep, narrow, fasciolar grooves. Terminal plate ovoid, gran- 

 ulate. 



Inferomarginals corresponding to superomarginals and extending 

 very slightly beyond them laterally, a longitudinal fasciolar furrow 

 separating the 2 series. They encroach upon the actinal surface 

 about as much as do the superomarginals upon the abactinal, but 

 their lateral surface is slightly more extensive, so that the extreme 

 width of the plates exceeds slightly that of superomarginals. The 

 plates are covered with slender, papilliform, slightly appressed 

 spinelets, and in addition proximally 3, then 2, and distally 1 

 slender, lanceolate, appressed spinules in the median transverse line. 

 The armature is similar to that of P. nuttingi^ but the spinelets and 

 enlarged spinules are slenderer and the latter are a little smaller. 

 The interbrachial plates of both series in nuttingi are a trifle nar- 

 rower and the inferomarginals project a little more laterally. 



Actinal interradial areas extensive; intermediate plates extending 

 in a single series half the length of furrow (to sixth inferomar- 

 ginal) and in 2 series a little over a third the furrow (to third 

 inferomarginal). The odd interradial series has 4 plates, and 

 extends from a pair of plates back of the jaws to the interradial 

 suture between the 2 first inferomarginals (as in P. nuttingi). The 

 plates have a conspicuous keel and carry a paxilliform group of 15 

 to 18 slender, rather long spinelets, those in center the stoutest and 

 prickly at the slightly expanded tips. The spinelets are slenderer 

 and longer than in P. nuttingi. 



Furrow spines slender, pointed, slightly compressed, in a regular 

 comb of 6, sometimes 7, the contour of the distal margin being 

 curved. Subambulacral spines, 12 to 16, slender, terete, with prickly 



