MONOGRAPH OF JAPANESE OPHIUROIDEA. 



159 



smaller one, the colour is vivid 

 green in alcohol ; the arms have 

 darker and lighter bands of the 

 same colour ; and each dorsal 

 arm plate has three wliite spots 

 on the outer margin, which are 

 especially conspicuous in the 

 dark bands. It seems that, in 

 this species, the colour changes 

 in alcohol from green to brown 

 in the course of time. 



Ophiactis gymnocJiora Clark. 



OpJdadis gymnocliora : Clark, 

 BuU. Ü. S. Nat. Mus., LXXV, 1911, 

 p. 139, %. 54. 



Tanega-shima (Clakk). 



Fig. 39. Ophiactis saviçpiyi. x 16. a. From 

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

 two arm joints near disk. 



Key to Japanese species and varieties of Opliioi^UoUs, 



A — One very large supplementary plate present on either side of each 

 dorsal arm plate, besides the smaller supplementary ones, .mirahilis. 

 AÄ — No especially large supplementary dorsal arm plates, though there 

 is present a row of small supplementary plates along the outer, and 

 often also lateral, borders of each dorsal arm plate. 

 a — Supplementary dorsal arm plates occurring along both the outer and 

 lateral borders of the primary ones ; oral papillae short and stout . . 



aculeafa. 



&— Arm spines short, stout, flattened, blunt; radial shields mostly or 

 entirely covered with granules or spines typical aculeata. 



