JAPANESE ASTEEOIDEA. 491 



inner row, arranged somewhat like the fingers of the human hand, 

 those of the middle part being much longer than those at the 

 ends, which are often very short. The individual spines are more 

 or less flattened and prismatic in shape, with rounded apices. 

 The spines of the outer row are much stouter than those of the 

 inner, and there are three or four on each plate. They are 

 more or less flattened and prismatic in shape, and are mostly 

 grooved longitudinally in the distal part; the apices are more 

 or less wedge-shaped. At the adcentral end of each plate 

 between the two rows of spines there is a large forcipiform pedicel- 

 laria, usually slightly curved, showing its upper portion above the 

 neighbouring spines of the inner row (PI. XIV, fig. 223 225). 



Moi(th-2)Iates.— As seen from the surface the mouth-plates 

 themselves are not very apparent, the space between the rows 

 of oral armature on either side being exactly like the rest of the 

 ventrolateral area. There are two rows of spines corresponding 

 to each mouth-plate ; the outer consisting mostly of two, sometimes 

 of three, spines, exactly like those of the outer series of the ad- 

 ambulacral spines in form, but larger, and lying in line with them. 

 The inner row of oral armature consists of nine or ten spines, of 

 which the three or four adjoining the first adambulacral plate 

 are shorter and more slender than the rest, are in all points more 

 like the spines of the inner row of adambulacral armature, and 

 lie in line with them ; these spines gradually become longer as 

 they proceed away from the first adaml)ulacral plate. The re- 

 maining six spines of the oral armature are subequal in length, 

 but become stouter toward the mouth, and the one at the 

 mouth end is particularly stout and nearly triangular in cross- 

 section. These spines are like those of the outer row of adam- 



