AXD ECHINOIDEA OF THE KOREAN SEAS. 425 



out into a comb overhanging the ambulacral furrow, is composed 

 of three papilla, the middle one being longer than the others ; 

 the outer series, which radiates towards the ventral plates, consists 

 in the middle of the arm of tbree papillse, whilst along the inner 

 fourth of tbe furrow there are four or five, these being arranged 

 two and two, or two and three togetber, one pair opposed to the 

 inner series, the others placed more external and nearer together. 

 On the innermost plates of the ray this external series of foot- 

 papillae is further augmented by two or tbree additional spinelets, 

 and which form an almost imperceptible transition into the scu- 

 ticles of the ventral plates. The ventral marginal plates bear three 

 spines — the uppermost, or that nearest the margin, being the 

 smallest ; the second is large, compressed and acuminate, twice 

 the size of the marginal spine, and is succeeded by another almost 

 as large. The spines are arranged obliquely across the plate, 

 except in the arm-angle, where they form a straight series along 

 with two or three additional spinelets which lie between them 

 and the furrow. The main spines of these inmost plates of the 

 arm-angle are also somewhat smaller than their successors. The 

 rest of the ventral plate is covered with numercu-s small com- 

 pressed and finely acuminate scuticles, standing erect and fairly 

 well spaced, which present quite a difierent appearance to the 

 flat, closely-packed, spatulate scales which so frequently clothe 

 the under surface of Astropecten. The furrows between the 

 plates are wide, having the margins set with fine setseform spi- 

 nules, very difl^erent from the armature of the plate just described. 

 The upper marginal plates, which are broader than long, number 

 about sixteen on each side, exclusive of the tip. They are closely 

 papillate ; and the spine-like papillae are cylindrical, with radiate 

 tips more or less expanded and quite clavate. There are about 

 five rows of these spinelets upon a plate, exclusive of the mar- 

 ginal setseform series, the middle ranges being larger than the 

 rest ; whilst the setseform spinelets which fringe the furrows are 

 much longer and more delicate, and present in a more marked 

 degree the clavate character of the tip. 



The paxillary area is, at the middle of the ray, a little broader 

 than the marginal plate (though not twice as broad) ; and the 

 paxillse are large and very distinctly stellate, 5-6-radial, with a 

 ray springing from the centre as well, though sometimes this is 

 wanting. The madreporiform body is situated close to the mar- 

 ginal plates. 



