2i 



NOMENCLATURE. 



fusiform IS . Fusiform; intermediate between co* 

 nical and ovate, or tapering and a little 

 ventricose. 



imbricata. Imbricate ; with plaits parallel to the 

 margin. 



inlemipta. Interrupted ; continued by new ac- 

 cretions, or additions of the shell. 



invohUa. Involute ; having the margin of the 

 exterior lip turned inward. 



lineis crlsputa. Wrinkled -, rendered rough by 

 flexuous lines. 



marginata. Marginate ; the sides of the shell 

 being thickened. 



olovata. Obovate ; nearly oval, but narrower and 

 produced at the base instead of the apex, 



perfoliata. Perfoliate ; having a horizontal suture 

 girt with a deflex or overhanging margin, 

 as if one shell were placed upon another. 



poly thai ami a. Chambered j divided internally by 

 various partitions. 



ladicata. Radicate ; affixed by the base to some 

 foreign substance. 



rosirala. Rostrated 3 beaked. 



