MONOGKArH OF JAPANESE OPHIUROIDEA. 245 



two or three spines. It may be observed in some radii, that the 

 lateral plates of the first free arm joint are in process of being 

 absorbed into the pentagonal body. 



Colour in alcohol : whitish or light yellow ; central and radiais, 

 radial shields and inner part of the interradial spaces below bluish 

 gray. 



This specimen was found attached to a stone by the ventral 

 surface of the pentagonal body, in the same way as Chiton or 

 Patella. 



The present species difiers from the genotype, A. permira 

 Sladen from Madagascar, chiefly in the very regular arrangement 

 of the plates on the dorsal surface of the pentagonal body as a 

 whole, in the larger central plate, in the much smaller and quite 

 regular infi'abasals, in the much narrower basais and interradiais, 

 in the infrabasals, basais and interradiais being elevated so as to 

 form a regular symmetrical system of ridges, in the scarcely 

 joined and not overlapping radial shields, in the absence of the 

 central boss on the primary plates, in the very regular and much 

 narrower dorsal arm plates, in the much smaller and rather incon- 

 spicuous madreporic shield, in the longer adorai shields, in the 

 oral plates, being somewhat narrower and in contact to a less 

 extent, in the perfectly saddle- shaped ventral arm plates and in 

 the much narrower free portion of the arms. Further, this species 

 differs from Chun's Astrophmra from Agulhas Bank, which is not 

 yet named, cliiefly in the smaller and regular infrabasals, in the 

 narrower basais and interradiais, in the elevated infrabasals, basais 

 and interradiais, in having two, instead of three, sets of inter- 

 radials^\ in the not overlapping radial shields, in the absence of 



1) The presence of two or three sets of interradials may not be of specific vnhie, because 

 Kœhleb has observed both cases in his ,4. cavellœ. 



