6S PROF. K. J. BELL ON THE [Fel). 19, 



Adambulacral spiniilation essentially triplacanthid, but care is 

 required iu determining the cliaracters of the third row. The 

 plates which carry the spines are strongly convex towards the 

 ambulacral groove ; six spines in each innermost series, of which 

 the median are distinctly the longest ; none are particularly delicate. 

 In the middle row there is generally only one spine, which is then 

 of considerable stoutness ; sometimes a smaller is added to it; those 

 of the third row are most conspicuous when they form a process 

 about half as prominent as the median spine ; sometimes it is diffi- 

 cult to distinguish them from the granulation of the disk. 



The arrangement of the ventral ossicles may be made out, as the 

 granules which invest them are loosely packed and are of some 

 s^ize ; the granules on the marginal plates are much more closely 

 set, are smaller, and form a more regular pavement ; the granules 

 are very numerous on the dorsal aspect, tending to be convex, but 

 differing a good deal in size and shape ; the poriferous areas are 

 small, as the ossicles are individually large ; the lophial series of 

 ossicles have their long axes set at right angles to the long axis of 

 the arm ; on either side another series of ossicles reaches to the ends 

 of the arms, while another proceeds about halfway down ; some 

 three or four ossicles form a short series outside these last ; so that 

 the whole disk is marked by regular rows of convex ossicles. The 

 madreporic plate, as so frequently happens in this genus, is not far 

 from the apical region, is of a moderate size, and fairly prominent. 



Colour, when first dried, probably brownish. 



Measurements:— R = 60, 46, 45, 41 ■,r = 29, 22, 19, 18; greatest 

 width of arm 19, 18. 



ffab. Australia (Swan River ; Fremantle). 



Oreaster chinensis. 



Pentaceros chinensis, Gray, Ann. N. H. vi. p. 276. 



Oreaster chinensis, M. Tr. Syst. Ast. p. 46. 



The type of Gray's species is now lying before me, and it answers 

 so well to the description given by Miiller and Troschel that I feel 

 confident that Mr. Edgar Smith took a correct view when he 

 attached to its board the words, " The same, I believe, as Oreaster 

 chinensis, Miiller and Troschel." 



It will be convenient to give here a diagnosis of the species, 

 couched in similar terms to the others here described. 



R=2'7>'. Disk rather high, arms pretty wide at their base, 

 narrowing towards the tip ; lophial ossicles without spines, save the 

 apical, which are rounded and knob-like ; four spinous projections 

 within the apical region. 



18 plates in either marginal series ; the inferior quite ventral in 

 position, and not set regularly (in the middle line of the arm) 

 below the superior ; in the angle of the arm one or more of the 

 superomarginals may be provided with short but sharp spinous 

 projections ; all or nearly all the inferomarginals bear short spinous 

 processes ; bare of granules. 



