AND ECHINOIDEA OF THE KOEEAN SEAS. 



431 



1876. Pentagonaster (Stellaster) Belcheri, Perrier, Stell&ides du Mu- 

 seum, Arch, de Zool. exper. et gen. t. v. p. 42. 



Coll. St. John : Korean Straits, 50 fathoms. 



In the type specimen figured and described by Dr. GTray, a 

 group of two or three small tubercles is situated upon the disk in 

 each radial area at about the same distance from the centre as the 

 madreporiform body, whilst further outward, at the base of the 

 arm, stands a single isolated tubercle, likewise in the median line 

 of the ray. 



In an example oiS. Belcher i from Australia, which Dr. Liitken 

 has described, this latter tubercle is wanting ; and from the cir- 

 cumstance of the specimen being much smaller than that of G-ray's 

 (measuring only r =8 millims., E,=25 millims.), Liitken has been 

 led to regard the presence of this isolated tubercle at the base of 

 the rays as merely a dependence on age and growth. 



The present specimen is smaller than either of the above, and 

 is interesting from the fact that the only tubercles which it pos- 

 sesses are a single one in each radial field. Each of these occu- 

 pies the middle of a plate which is situated rather further than 

 the madreporiform body from the centre of the disk, and is sur- 

 rounded by several small granules markedly larger than those 

 which cover the plates generally. The disk is moderately convex, 

 the radial areas gibbous, and the interradial ones depressed. The 

 semidiameters of the disk and rays measure 7 millims. and 19 

 millims. respectively. 



The inner row of foot-papillse form a compact comb on each 

 interambulacral plate, arching upward over the furrov^r and having 

 in each group 5-6 papillae, the ad- and aboral being smaller than 

 the others. The outer series consists of a single small, short, 

 stout papilla placed opposite to the middle of the inner row, and 

 having two or three papillate granules on each side, sometimes in 

 line and sometimes behind it, the whole forming a more or less 

 regular line parallel with the inner series. Occasionally a few 

 additional granules form an irregular reduplication of this series, 

 whilst upon the inner portion of the furrow the granules which 

 stand near to the main single papilla gradually increase in size, 

 the distinction between them becoming almost imperceptible. 

 There are but few pedicellaria valvulatce on the dorsal surface, 

 and none on the marginal plates. The marginal spines are com- 

 pressed, not tapering towards the tip, which is rounded. Upon the 

 two outer thirds of the arm there is only a single plate in the dorsal 



