48 NATICA. 



contracted b^' the broad, thick callus ; white, under a thin 

 yellowish white epidermis. Length, 18 mill. 



W. Coast of South America. 

 A species of no marked character ; perhaps not distinct from 

 N. uber, Yal. N. elongata, Troschel (fig. 84) appears to be 

 identical. 



N. UBER, Val. PI. It, figs. 61, 66. 



Shell white, polished, under an extremely deciduous thin 

 epidermis, columella densely enameled, usually covering the 

 upper part of the narrow, deep umbilicus. Length, 1-1 "5 inches. 



Peru, Panama^ Mazatlan. 



Carpenter wrote of this shell : " The extreme forms of this 

 species are so dissimilar as to have warranted their separation. 

 An examination of some hundreds of specimens, however, 

 shows that there is no consistency in the types. The shell is 

 either thin or heavy ; subglobular or very transverse ; with the 

 umbilicus quite open, or reduced by the callosity to a mere 

 chink ; the callus varying greatl}^ in shape and intensity. The 

 callosit}'' projects considerabl}^ beyond the aperture, leaving a 

 sutural groove. Umbilicus more or less slightly spiral." 



Carpenter includes N. uberina of Adams' Genera, N. ovum, 

 Menke, and N. r-apulum. Reeve ; also, somewhat doubtfully, N. 

 alabaster, Reeve — which I have described separatelv. To this 

 list is to be added N. virginea, Recluz (fig. 66), and possibl}' 

 several of the species from western South America — dubia, 

 Recluz, cora, d'Orb., etc. Finally, I can distinguish forms of 

 N. uber from the Pol^^nesian and East Indian N. mamilla in no 

 way except by habitat. 



N. Panamensis, Recluz. PL 17, fig. 60. 



Compressed on the sides into a quadrangularly ovate form ; 



white, under a deciduous horn-colored epidermis ; umbilicus 



narrow, nearly filled by the columellar callus. 



Length, 1*5-2 inches. 



Panama. 



The peculiar form described above appears to be characteristic 



of the species. 



