D.r- 



LEDA (H3BELSDA) BOWDIITIAI'IA n. sp. 



Peseription .- Shell small, decidedly convex, transvexSel;, 

 elongate, outline sub-trigonal posteriorly rostrete, subequilat- 

 eral, dorsal marp-ins with steep slopes, the anterior being con- 

 vex anfl the posterior concave; produced and abruptly roixnded 

 anteriorly; posterior margin forming a short blunt rostrum; 

 broadly and symmetrically arcuate vent rally; umbones apr^roximate- 

 ly central in position, high, very tumid, strongly incurved and 

 opisthogyrate ; area behind the umbo flattened; posterior carina 

 low, broad and very feeble distally; external sculpture of irreg- 

 ularly spaced, poorly developed, fine impressed lines, obsolete 

 on the umbones and in the area within the posterior carina, and 

 coinciding v;ith the irregularly spaced lines of growth in the 

 distal half of the shell; chondrophore triangular, relatively 

 broad; teeth in two series, with about nineteen in the slightly 

 convex axiterior series and about thirteen in the co..cave poster- 

 ior series, the median teeth being small and obscure; muscle 

 scars faint, rela^^ively large; pallial line obscure. 



Di: ens ions ,- length, 6.2 mm.; alt., 4,5 mm.; semidiam., 

 1,9 mm. 



Remarks .- i'his species, the t;. ne of the section, is 

 described from several valves v;hich display constant characters. 



