MONOGEAPH OF JAPANESE OPHIUROIDEA. 239 



stout with well developed lateral wings, the basal vertebriG very 

 short and discoidal, tho second being the shortest, and the teeth 

 squarish and very stout. In all these representatives of the 

 Ophiolepidince, the genital plate and radial shield articulate with 

 each other by means of two condyles and one pit on both the 

 plates, and the genital plate and scale articulate with each other 

 at some distance inwards from the outer end of the latter. 



Astrophiura Sladen, 1878. 



Basal portion of arms very intimately united with the disk 

 proper, so as to form with it a pentagonal " asteroid " body, of 

 wliich the dorsal surface is entirely covered over by the stout 

 primaries and radial shields of the disk proper and by the dorsal 

 and much widened lateral arm plates of the much modified arm 

 bases. The interradial borders of the " asteroid " body are 

 hemmed by a series of modified arm spines, which are soldered 

 together. The basal lateral arm plates articulate with the vertebrae 

 by means of a bar-like ridge. Arms -outside the " asteroid " body 

 very abortive, without dorsal and ventral arm plates, without 

 tentacles. Tentacle pores present only within the " asteroid " 

 body, very large and arranged so as to form a pentamerous 

 petaloid series. Ventral arm plates well developed, forming a 

 continuous series, which extends only as far as the last tentacle 

 pores. Oral shield single or five^^; in the former case, it is the 

 madreporite. Adorai shields long and narrow. Oral plates rather 

 stout. A single dental plate is present at the apex of each jaw. 

 »Six or seven oral papilla^ to each jaw, arranged in a single series, 



1) A. cavella; Kœhlkk, 1015, has five oral shields. 



