JAPANESE ASTEP.OIDEA. 461 



only at the abcentral end of the mouth-plate, and consists of only 

 three spines, which are nearly as stout as those of the inner row 

 and similar in form, although more irregular. 



Ventrolaterals. — The ventrolateral plates are very numerous 

 and small and very irregular both in size and arrangement. In 

 the greater part of the arms there is a somewhat irregular, con- 

 tinuous series of plates between the adambulacral plates and the 

 inferomarginals, besides a few small, intercalated plates which 

 occur here and there ; but in the disk the ventrolateral plates arc 

 entirely destitute of any regular arrangement. The plates of the 

 arms are covered with granules similar to those of the infero- 

 marginals, but in the disk the granules are very coarse and tend 

 to become conical and spiny towards the corner of the mouth. 

 More or less transversely elongated, valvate pedicellarise are very 

 numerous on the ventrolateral plates. They are of various sizes ; 

 some may be as long as 2 mm. but others may be only half as 

 long or less. The smaller valvate pedicellaricB are particularly 

 numerous in the disk on either side of the ambulacral furrows. 



Ahadinal plates. — The abactinal side consists of more or less 

 irregularly stellate plates of comparatively small size, except in 

 the most distal part of the arms, where the plates are either 

 round or elliptical and are closely crowded. The processes of the 

 stellate plates may or may not be united with similar processes 

 of the neighbouring plates, and hence the meshes may not be 

 always closed. There are five particularly large, conical tubercular 

 adcentral plates enclosing a central depression, in which there are 

 a few irregular ossicles. Each adcentral plate has some eight 

 radiating processes, wliich are united with similar processes of the 

 neighbouring plates, and although in the specimen before me the 



