MONOGRAPH OE JAPANESE OPHIUROIDEA. 89 



smaller and more numerous than on the dorsal surface of the 

 disk. Oral region surrounded by a circular groove, and distinctly 

 set off from the outer parts. Oral angles strongly puffed down- 

 wards, covered with close-set granules of various sizes. Teeth 

 and dental papillae similar, spiniform, short and slender, acute, 

 forming vertical clumps at the apices of the jaws. No oral 

 papillae. 



Arms rather stout, uniformly tapered towards the extremity, 

 dorsally and laterally with raised and depressed annuli ; on the 

 raised annuli, the granules are coarser, rather distinct and well 

 spaced, arranged in four irregular rows, of which the middle two 

 bear hooks, the series of hooked granules l^eing interrupted by 

 smooth ones ; on the depressed annuli, the granules are very fine 

 and form a smooth covering, with many small, oval plates, which 

 are sunken below the plane of the granules. Ventral surface of 

 the arms covered by the continuation of the ventral brachial 

 space of the disk, with a pavement of irregular plates, which are 

 so arranged as to bring about transverse wrinkles in the skin, 

 and bear smooth, scattered tubercles, which distally become smaller 

 and indistinguishable from the smooth granules. No arm spine 

 to the first tentacle pore ; one or two spines to the second ; two 

 or three spines to the third ; and three or four spines to those 

 beyond ; but only two spines to each pore near the extremity of 

 the arm. The arm spines are peg-like and flattened, and terminate 

 with three or four thorny points ; those situated adradially are 

 somewhat longer than the abradial ones, and beyond the basal 

 arm joints the most adradial spine becomes almost as long as the 

 corresponding arm joint. 



Colour in alcohol reddish or yellowish brown. 



In younger specimens, the disk tubercles are much less 



