JAPANESE ASTEEOIDEA. 241 



/ 



end of plate ; or the spinnles may be disposed like rays of fan and gi'aduated 

 in length toward either end of series. (2) On actiual surface are about 3 

 longitudinal series of smaller spinelets, decreasing in length toward outer 

 edge of plate where the spinelets are like those of actinal intermediate 

 plates. Four spinelets commonly occur in the inner actinal series and about 

 3-5 in each of the outer ; or the 2 latter series may be wanting, the 

 spinelets, instead, forming an iiTegular group, especially on outer part of 

 ray where there are frequently upwards to 16 or 20 actinal spinelets. 



" Mouth plates naiTOw, rather prominent actinally, the free margins of 

 the combined plates forming a sahent angle into actinostome ; free margin 

 of each plate shghtly angular near inner end and longer than the margin 

 adjacent to first adambulacral. Armatm-e consists of a fm-row series of about 

 6 or 7 tapering spinules decreasing in length from the inner enlarged tooth, 

 outward, and thence continued along margin adjacent to first adambulacral 

 in about 9 much smaller spinelets similar to those of actinal intermediate 

 plates. A superficial series of similar spinelets follows margin of median 

 sutui'e, increasing in size toward inner augle of plate, and an incomplete 

 more or less irregular series often, but not always, occurs between marginal 

 and superficial series. There is more or less variation in the details of 

 dental armatm-e. 



" Madreporic body rather large, about midway between centre and ex- 

 treme edge of disk. Striations coarse, centrifugal, very irregular ; madreporic 

 body sometimes nearly liidden by 5 or 6 large paxillœ. 



"Type, No. 21926, U. S. Nat. Mus. Type locahty. Albatross Station 

 3310, Bering Sea, in 58 fathoms, on dark sand and mud. 



" RemarJtS. — Tliis species bears a close resemblance to Parastropecten 

 inermis Ludwig'^ and is probably congeneric with that form, although anomalv.s 

 Las a minute anal pore. The presence of an anal pore is, I believe, a 

 character of scarcely more than specific impoiiance. For instance one species 

 of Astropeden has been show^n by Veeeill to possess a minute anus. Al- 

 though I have not yet had an opportimity to make serial sections of the 



1) " Mem. Mus. Comp. Zool., xxxii, July, 1905, 76, pi. iv, fig. 21, 22 ; pi. xxi, fig. 117 pi. 

 xxii, fig. 126. (Gulf of Panama and Cocos Id., 1,271 and 1,408 meters.) " 



