of spinose ri^os, the \--:''p-:"^en±n^ ones being f'^pe from spines, 

 longitudinally finelj' striate, and ahoTsai v/hen very perfect miniite 

 scales. -^^he adult shell is rather short and rounded and less in- 

 flated than usual in the genus, 'i^he specr-p is remarVahle for its 

 small hin.p-e -area." (JJall, 1898). 



Tvro inmcture left valves apparently? should "be assigned to this 

 species. They are thin, slig-htly auriculate, slightly inflated, 

 moderately ineqiiilatoral, the posterior side heing more produced; 

 ujnbones very low, weakly inflated; external surface sculptured 

 with a varying niimher (ten ■^'^ :^ifteen) of I'^w, primary radial ribs, 

 bearing at irregular intervals short, relatively stout spines; 

 second.ary radial ribs and strir:e of irregular width intercalated 

 between the primaries, transversely roxigheioed or slightly spinose; 

 in the interval between two primary ribs one secondcry rib Tisually 

 more prominent and more obviously spinose than the others; auricles 

 poorly developer!, their surface omaniente'l with a few small spines 

 or scales; cardinal area very narrow; innfer margin of the valve ir- 

 regul-^rly and feebly erenulated. 'Ihe dimensions ~f the lar-^er are: 

 1st., 1?..- :a':i. ; alt., IJ^'.l ii^m. ; '"'iam., £.5 mm..; length of hinge, 

 6. 5 ram. ; 



A very small, proriortionately mr ravey^ left vel: 



soubtfully referre'^ to this soecies; it has the seconc' ary rr.disls 

 suT)pressed and the few spines near the ventral marp^in are .dorso- 

 ventrally coraioresser! . 



