_ 4^^ - 



tj^,. uj.. 



Desoriptioj] .- Shell j s.r ,':"". "^ , " borate 



in outline, p-^--^- ' "■ , '.r. anteri'j uiore con- 



verl^^^ than the posterior; i^jiihones fiill, moderately' " ' " ; external 

 surface sculptured with thirty-five lou , flat, "oro ^ ial ri'bs, 



overhaxigin' narrow, cli-epl^- c" ui^^i.-T' '■■''■' ' ^-ces; the 



dis^-al portions of the anterior four or five riv "^.ing to 



he ohsolete, producing- an almost smoo"n, slir - ilated area; 



t'ne next ■^■-'--'-- three rihs haviiig icli.:., _;.].most microscopic, 

 londitudinal striae and fine concent ic mar'Cin.g'S, more "•promi- 

 nent and oblique on the anterior rihs of this series ^.tlc', arched 

 on '':he regaining ai±^^, _ ^-es of -'-'"'■ :'" , i-lly on the 



anterior side, finely; nodulate:"; tl ' ': two oj o inter- 



spaces of this series not channelled, hut fiT' ^^osterior 



eight riho distally scarcely .. " "^■'■"' '"' '"■' " ' '""'' 



lines, the lines ht ;-: broader i " " o, 



the ribs being cro£ trica" " , ' ic 



z-^.T'.^e and the last thre- , n their 



rozimal half, small .-"Ic" ' " '^"x "^^--e 



valve feebly '^l half -^face 



'" ' - Tulrji runni:, -xv'.... 



~Ji":;ensions.- T.at., .. ; alb., 6" mm.; semi ' ., r.^.-> 



