NERITACEA. MOLLUSCA. NATICA. 235 



which some specimens are said to be immaculate. But that shell has 

 a more elongated spire, a broader aperture and base, and its greatest 

 breadth is rather below instead of ratlier above the middle, as in this 

 species. It is the smallest species with which I am acquainted, though 

 I have seen one specimen f of an inch in length ; and, for so small a 

 shell, it is remarkable for its solidity. 



Natica canalicula'ta. 



Shell ovate, smooth, covered with a dusky yellow-colored epider- 

 mis ; ivhorls four ; spire channelled at the suture ; umbilicus a mere 

 line. 



Figure 161. 



State Coll., No. 43. 



Natica canaliculata, Gould ; Sltliman's Journ., xxxviii. 107. 



Shell ovate, rather ponderous, dingy-white, nearly smooth, 

 and somewhat glossy, covered with a dark gamboge-colored epi- 

 dermis ; whorls four, the upper portion of each turning before it 

 joins the preceding whorl, so as to form a broad, shallow canal at 

 the suture, and giving the spire a turreted appearance ; aperture 

 about two thirds the length of the shell, nearly semicircular ; lip 

 sharp, a little spreading in front, the inner margin nearly a straight 

 line, and overspread with a thick callus ; interior white ; umbilical 

 opening a mere slit, one side of which is formed by the callus, 

 sometimes altogether concealed ; operculum horny, sub-spiral. 

 Length l^^ inch, breadth ^-^ inch. 



Taken from fishes caught on the Banks, and one fine specimen 

 from a fish caught in Massachusetts Bay. I have a specimen also 

 from the coast of Norway. 



The aspect of this shell is such, that I was first led to refer it, 

 doubtfully, to the genus Paludi'na. It very greatly resembles Paludi- 

 na ponderosa, Say. All doubt, however, on that point, has been since 

 happily removed through the kindness of Colonel Totten, who furnished 

 me with several specimens containing the sub-spiral operculum. 



The remark of Deshayes, that Na'tica is without an epidermis, will 

 not hold good in regard to this species, nor, indeed, to any of 

 the species found on our coast. He, however, was aware of the small 

 value of this characteristic, and alludes to a species then under his 

 eye, which I take to be N. heros, having the shape and epidermis of 



