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the tip of the arms. It may also be remarked that in the inter- 

 radial sulci the tabula are pronouncedly rhomboidal in form. The 

 peripheral granules of the paxilla? are usually smaller than the 

 more central ones (PI. Xf, fig. 169). The pedicel lariae are numerous 

 on the abactinal surface and are well characterised by Sladen. 



The granules covering the superomarginal plates are so very 

 small and close set that the plates appear to the naked eye as if they 

 were covered with a tumid membrane. The presence of a naked area 

 on the abactinal surface of the superomarginal s is a characteristic 

 which this species shares with some others. The size of this area 

 varies much even in the same specimen, sometimes occupying, as 

 Sladen says, nearly the whole of the abactinal area, but sometimes 

 being very small. In the latter case the area is close to the inner 

 margin of the plate and its form tends more to be elliptical ; it may 

 occupy less than one half of the abactinal surface. On some of 

 the regenerated plates this area is totally absent. The pedicel- 

 lariœ may be situated close to the naked area or may be farther 

 removed from it. 



The inferomarginal plates are mostly coincident with the 

 superomarginals, but as they approach the tip of the arms the 

 two series become distinctl}" alternate. In some of the interradii, 

 also, they are strictly coincident only for one or two plates on 

 either side of the interradial line. There is a naked area on 

 each plate on the actinal surface. 



The furrow series of the adambulacral armature consists 

 usually of five, but sometimes six, rather short, stout, truncate 

 spines of a prismatic form, and is separated from the granules 

 covering the actinal surface of the plates by a distinct space, 

 forming a groove on either side of the ambulacral furrow (PI. XI, 



