DILOMA. 419 



clathratus, A. Adams. lacteus, PJiil. 



deiiigratus, Chem. oxytropis, Phil. 



Dimkeri, Koch. Philippii, Koch- 



edeutulus, A. Adams. Philippinus, A. Adams. 



exasperatus, A. Adams. pullatus, Phil. 



foveolatus, A. Adams. puuctigerus, ^. Adams. 



gemmatus, Gould. ruber, A. Adavis. 



Guttadauri, Phil. Straugei, A. Adams. 



borridus, Phil. sulciferus, A. Adams. 



incisus, Mke. triciugulatus, A. Adams. 

 iuconspicuus, Phil. 



Sub-gen. perrinia, H. and A. Adams. 



Shell trocbifonn ; wborls flattened, cancellated ; aperture 

 quadrangular; columella nearly straight, with several tubercles 

 at tbe fore part ; outer lip strongly Urate internally. 



auguliferus, A. Adams. lirostoma, A. Adams. 



Genus DILOMA, Philippi. 



Shell conoidal, smooth, imperforate, umbilical region 

 covered with a thin, porcellanous expansion of the colu- 

 mella ; columellar margin produced anteriorly, forming 

 an elevated ridge round the inner margin of the outer 

 lip. 



Ex. D. nigerrima, Chemnitz, pi. 47, fig. 7. Oper- 

 culum, D. nigerrima, fig. 7, a, 7, h. Shell, D. nigerrima, 

 fig. 7, c. 



This genus closely resembles Oxystele, the columellar 

 margin, however, does not extend into the outer edge of 

 the labrum, but forms an elevated border within and 

 parallel to it. 



