MONOGRAPH OF JAPANESE OPHIUROIDEA. 



251 



Fig. 69. Aspidophiura icatasei. x8. a 

 From above, b. From below, c. Side view 

 of three arm joints near disk. 



pentagonal central, and the 



hexagonal radiais have each a 



small bat conspicuous, mamelon- 



shaped central boss. Central 



somewhat smaller than the 



radiais. The first interradiais 



are pentagonal, or qaadrangular 



with irregular inner edge, about 



as long as wide, wider within 



than without, a little smaller 



than the radiais, but larger than 



the second interradiais, which 



are quadrangular, wider than 



long, and wider without than 



within. Radial shields about as 



large as the radiais, as long as wide, irregularly triangular, with 



convex abradial side, apposed to each other by their entire length. 



At the meeting points of the radiais, first interradiais and radial 



shields, a very small, thick, convex plate is present, and may be 



duplicated. Radial scales of moderate size, semilunar, with acute, 



needle-like comb papillae. Interbrachial ventral surfaces entirely 



covered over by the large, stout genital scales and a very large, 



stout plate. Genital slits widened at the inner end, bounded by 



minute, rather well spaced papillae. 



Oral shields large, stout, triangular as a whole, with widely 

 rounded outer angles and obtuse inner angle, and convex outer and 

 lateral sides, the latter with a blunt notch near the inner end, 

 corresponding to the genital slit ; about as wide as long, wider 

 without than within. Adorai shields narrow, of uniform width, 

 meeting with each other. Five oral papillae on' either side. 



