JAPANESE ASTEEOIDEA. 453 



largest spines of this row usually reaches the base of those of 

 the next row, which consists typically of two or three stout, 

 flattened, blunt spines, like those of the corresponding row in 0. 

 magnificus. These spines may be subequal or very unequal, and 

 sometimes one or more of them may be so entirely out of the 

 row that the latter becomes duplicated. The third row consists 

 of one to three spines similar in shape to those of the second 

 row, but usually smaller. On the adcentral border of each ad- 

 ambulacral plate there are one or more forcipiform pedicellarise, 

 and on some plates they may form a row reaching up to the out- 

 side of the third row of spines. They may be shghtly curved or 

 perfectly straight, and are usually smaller when there are more. 

 There may be in addition one or more forcipiform pedicellariae 

 either in line with or outside the third row of spines. 



Mouth-plates. — As is usual in this genus the mouth-plates 

 themselves can not be seen from the surface, but the spines are 

 very conspicuous, and consists of two rows. In the inner row 

 there are 11-13 spines, of which the four or five at the mouth 

 end are stout and prismatic in form and larger than the rest. The 

 outer row consists of three or four spines, similar in shape to 

 the larger spines of the inner row, and is confined to the abcen- 

 tral end of the mouth-plates, on the interradial side of the smaller 

 spines of the inner row. 



Ventrolaterals. — The ventrolateral plates are as a whole more 

 regular than in 0. magnificus, and easier to distinguish from the 

 surface. One regular row of plates can be made out on either 

 side of the ambulacral furrow, extending from the tip of the arms 

 to near the mouth, where it is merged in among the plates 

 occupying the mouth corner. A second, somewhat irregular row 



