— Ori - 



Section HelDeleda n. sect. 



Et7;molo°:y .- KeTDes,- "blimt; leda. 



Shell smsll, decidsf.ly inflate'-^, sub equilateral, bluntly 

 rostrated; posterior carina subrounded; area behind the umbo 

 flattened, but not impressed; e:cternal sitrface sculptured with 

 concentric lines usually obscure and irregularly developed; hinge- 

 teeth in two subequal series, separated by a relatively wide tri- 

 angular chondrophore; -ligament apparently entirely internal. 



Type .- I. bowdenisna n. sp. 



This section is proposed f^r the reception of two species 

 and a variety - all new - which form a homogeneous group, sharp- 

 ly differentiated from the associated Lerias. The group is char- 

 acterizec! by its strongly inflate!, bluntly rostrated form. I. 

 due r den i n. sp. , the shortest of the three forms constituting this 

 section, externally bears some resemblance to certain rostrated 

 forms of the genus Tindaria, such as T_. smirna Dall , a deep-water 

 species from the &ulf of PanaLia, but aside from other considerations, 

 Tindaria has an exteraal ligament. L. pontonia Dall, dredged near 

 the Galapagos Islands, appears to belong to the group under con- 

 sideration. Through forms v;hich are more sharply rostrated, less 



convex and more obviously sculptured Kebeleda grades into Jupi- 

 teria. 



