NATICA. 35 



*** 



N. LARVATA, Canefri. PL 23, fig. G4. 



Smooth, very minutely decussately striate, subplicate at the 

 suture ; bluish white, with two indistinct chestnut bands ; umbil- 

 icus entirely filled by a heavy white columellar callus ; aperture 

 chestnut-colored. Length, 18 mill. 



Hob. unknown. 



The operculum has not been observed, and the systematic 

 position of the species is uncertain. 



Section LUNATIA, Gray, 1847. 

 N. LEWISII, Gould. PI. 13, figs. 11, 12 ; PL 9, fig. 70. 



Conical globose, obsoletely spirally striate, yellowish white or 

 brownish white ; whorls obliquely sloping above with, in old 

 specimens, an obtuse angle on the shoulder, defined by a slight 

 concave constriction above and below it ; interior chocolate- 

 white ; umbilicus narrow and deep,with a tongue-shaped, chocolate- 

 tinged callus extended partly over it from above. 



Length, 3-5 inches. 



California, Oregon, etc., Japan. 



The largest species of the genus. Small specimens are regu- 

 larly rounded on the upper portion of the whorls ; it is only with 

 advancing age that the constriction gradually becomes more 

 apparent. The species is generally known as N. herculea, Mid- 

 dendorff, but that name was published two years subsequently. 

 N. Beiniana, Dunker (fig. 12), a Japanese species, is surely a 

 synonym ; and N. algida, Gould (fig. 70) is the young. 



N. IIEROS, Say. PL 13, figs. 13, 1C ; PL 14, figs. 19, 20. 



Yellowish, or brownish white, with obsolete waved minute 

 spiral striae, interior flesh-color, columella only slightly callously 

 thickened, flesh-color, scarcely contracting the narrow, deep 

 umbilicus. Length, 3-4'5 inches. 



Maine to New Jersey. 



N. heros is a northern species, gradually replaced southwards 

 by N. duplicata. The latter has been confounded with it by 

 British authors. Like N. duplicata, it preys extensively on 

 other mollusks ; on the New Jersey coast Mactra solidissima is 

 its usual victim, being grasped in the voluminous foot of the 



