54 



BULLETIN lOO, UNITED STATES NATIONAL MUSEUM. 



Specimens examined. — In addition to the type, 4 from the follow- 

 ing stations : 



Station 5537, between Negros and Siquijor, 254 fathoms, green 

 mud, bottom temperature 53.5° F. ; 1 specimen. 



Station 5541, off Point Tagolo, northern Mindanao, 219 fathoms, 

 jBne sand, broken shells, bottom temperature 53.3° F.; 1 specimen. 



Station 5565, between Jolo and Tawi Tawi (east of northern 

 Borneo) 243 fathoms, fine sand, shells; 2 specimens. 



Remarks. — This species resembles more closely the Atlantic form, 

 P. elegans Verrill than it does either gracilis or megaloplax. I have 

 been able to compare the type with a specimen of elegans from sta- 

 tion 2400, Gulf of Mexico, 169 fathoms. The differences are con- 

 trasted below : 



analogus. 

 Paxillae at base of ray with 1 cen- 

 tral and 9 or 10 peripneral spinelets ; 

 paxillae not close-set on disk ; smaller. 



Intervening ridge between mar- 

 ginal fascioles about half as broad 

 as the fascicle, or even less than half 

 (in interbrachium). 



Fasciole between iuferomarginals not 

 narrowing toward the actinolateral 

 angle of ray (as marked by the lateral 

 spine). Inferomarginal fascioles on 

 lateral face of interbrachium not nar- 

 rower than the superomarginal fas- 

 cioles. 



In interbrachium the fascioles or 

 cribriform organs are slightly open, 

 and are deeper, with more numerous 

 spinelets. 



Inferomarginal spines larger. 



Actinal surface of iuferomarginals 

 narrower, without granulations ; In- 

 terradial inferomarginal plate bor- 

 dered by about 6 or 7 spinelets, be- 

 tween the large actinolateral spine 

 and the inner margin of plate. 



Nine to 11 furrow spines, there be- 

 ing an enlarged spine on the distal 

 transverse border of plate beyond the 

 proximal third of the ray. 



First 10 adambulacral plates are 

 separated from the actinal Interme- 

 diate plates by a longitudinal fasciole. 



elegans. 



Paxillae at base of ray with 7 or 8 

 central and 15 to 17 peripheral spine- 

 lets ; paxillae close-set on disk and 

 larger. 



The intervening ridge as wide as 

 the fasciole. 



Inferomarginal fascioles of lateral 

 face of interliraehium narrowing to- 

 ward the actinolateral angle of ray; 

 the fascioles are narrower than the 

 corresponding superomarginal fasci- 

 oles. 



The fascioles or cribriform organs of 

 interbrachium are closed, the combs 



meeting in the middle of the fascioles. 



Inferomarginal spines smaller and 

 sometimes absent from first 2 or 3 

 plates. 



Actinal surface of inferomarginal 

 plates with about 12 tiny granuliform 

 protuberances or bosses under the 

 skin ; interradial inferomarginal plate 

 bordered by 11 or 12 spinelets be- 

 tween the actinolateral si)ine (If this 

 is present) and inner margin of plate. 



Twelve furrow spines, there being 

 no enlarged spine on the distal trans- 

 verse border of the plate. 



Only the first 3 adambulacrals are 

 so separated. 



