MÖNiOCxRAPH OF JAPANESE OPHIUROIDEA. 



209 



the abradial and inner borders of the radial shields, where it is 

 covered by fine, imbricating scales, arranged in four or five rows 



on the inner border but in 

 only one on the outer part of 

 the abradial side, and finer in- 

 wards than outwards. Naked 

 part of radial shields large, 

 pear-seed-shaped, more than 

 half as long as the disk radius, 

 more than twice as long as 

 wide, hardly in contact with- 

 out, slightly divergent within. 

 Interbrachial ventral surfaces 

 also covered by a soft naked 

 skin. Genital slits long. 



Oral shields rhomboidal, 

 or pentagonal with a very short 

 inner side and a much round- 

 ed outer angle ; wider than 

 long ; madreporic shield much 

 larger and almost circular. 



Fig. 57. Amphmra œsiuar'd xlO. a. From 

 above, h. From below, c. Dorsal view of 

 three arm joints at about one-third of the 

 arm length from the base. d. Side view of 

 three arm joints near disk. e. Side view of 

 three arm joints at about one-third of the 

 arm length from the base. 



Adorai shields triangular with 

 concave adradial side, tapered within, where they do not meet. Two 

 pairs of oral papilla? in each oral angle ; apical ones oval and very 

 stout ; distal ones spiniform, obtuse, arising from the adorai shields. 

 Besides, there occurs one spiniform papilla on either side just 

 above the distal one. 



Dorsal arm plates transversely oval, twice as wide as long, 

 successive plates in contact. Lateral arm plates not very 

 prominent, almost concealed by the arm spines, not meeting above 



