JAPANESE ASTEEOIDEA. 337 



species to P. imlcinus I reproduce the description of the latter at 

 full length [Alcock, '93, p. 90] : 



" Pentagonaster pulvimis, n. sp. 



"Rays 5. B,=2.2 r. E = 33 mm. in the type specimen. 



*' Near Pentagonaster mirahilis Perriek (Arcli. Zool. exper. vol V., 1876, 

 p. 40). 



" Disk pentagonal, much inflated abactinally and hoUowed actinally ; 

 rays relatively long and narrow, blunt-pointed, strongly upcnr\'ed in the 

 distal hah. The strongly convex abactinal sm-face of disk and raj's is 

 covered with hexagonal or j)olygonal plates, so close-set that, altliongh their 

 boimdaries are quite definite, no papulse are visible on denudation nor any 

 papular pores, and all closely covered with angular granules which show a 

 distinctly paxilliform arrangement ; the basal interradial plates are more than 

 twice the size of any of the other abactinal plates. 



" Marginal plates 17 in the upper, 19 in the lower series, measured 

 from mid-interbracliium to tip of ray, all ver}- closely and uniformly covered 

 with granules except the terminal six to eight in the supero-marginal series, 

 Avlüch have a central smooth boss. 



" Adambulacral plates with a furrow-comb of about seven uearlj' 

 equal-sized lamellar spinelets, and actinally with two longitudinal rows of 

 gi'anules, and between these and the fmTow a row of three coarse spinelets, 

 the ad central (adorai) of wliich is often replaced by a pedicellaria with two 

 spathulate valves. 



"Actinal sm*face deeply concave ; the actiual interradial areas are 

 large ; the actinal intermediate plates extend to the fourteeutli infero- 

 marginal, they are large and roughly quadrangular, and are so closely 

 covered with gi'anules that their limits are not easily discerned. 



" Ai"ms veiy indistinct. Madreporiform plate small and also very indis- 

 tinct ; it lies outside a much larger basal interradial plate, and is incon- 

 spicuous not merely because it is small, but also because its coarse discon- 

 tinuous vermicular erosions give it a gi-anular appearance much like that 

 of an ordinary j)late. 



