JAPANESE ASTEROIDEA. 27 



the nintli from the interradial Hne being about 8 mm. in length. The 

 surface of the plate is covered with membrane and bears no spines, except 

 occasionally a minute thornlet, irregularly placed near the base of the large 

 spine. 



"In the median interradial line there is one large odd supero-marginal 

 plate, developed abactinally into a prominent, truncate, conical tubercle, 

 upon which is borne a powerful robust spine about 8 mm. in length, direct- 

 ed vei-ticaUy, and thicker than any of the other spines on this species. 



" The infero-marginal plates are similar in form and character to the 

 superior series, each being nearly exactly Ijeneath its coiTesponding ui)per 

 companion. Like them, each has a x^ominent tuTiercular eminence, upon 

 which is borne a straight, robust, tapering, and sharply pointed spine, the 

 sixth or seventh from the interradial line measming about 10 mm. in length ; 

 the length decreasing slightly as they x^roceed along the ray. A second 

 similar but rather smaller spine, articulated on a tubercle, stands close to 

 the lateral spine on the inner side. The surfaco of the i^late is covered 

 with membrane ; and two or tln-ee irregularl}- placed microscopic thornlets 

 may be x^resent. On the two or three innermost jDlates on each side of the 

 median interradial line, the lateral spines and their comx)anions are gi'eatly 

 reduced in size, being little more than mere miliary sx)inelets. 



"In the interbrachial arcs, the marginal jjlates have the ax^pearance of 

 being brought over upon the disk ; and their surface forms a peculiar 

 bevelled area slox^ing outwards and downwards, the lower margin only of 

 the infero-marginal x^lates falling in the outline of the interbracliial arc. 



"The adambulacral x^lates are large and massive, of great breadth, and 

 rather broader than long. They are comparatively widely sex^rate, and the 

 interspaces are filled ux) with hgament ; the fuiTow margin is slightly convex. 

 Tlieir armature consists of : — (1.) a furrow series of five very small, short, 

 equal, cylindrical, obtusely x>oiuted sx^inelets, which radiate ax)art and form 

 a small isolated semicircular comb directed over the fm-row, the successive 

 combs being Avell sx)ac3d apart. (2.) On the actinal sui-fac3 of the plate 

 are two large, robust, tapering, but obtusely x>oiiited spinelets, x>laced one 

 beliind the other, wliich are subequal in length, or occasionally the outer- 



