348 NATICIDiE. 



to be occupied by one having been apparently thrown into the aper- 

 ture. Tliere is one other described species conforming to the same 

 type, the Natica fluctuata, Sowerby (Tankerville Catal. p. 12), and 

 figured by Dr. Jay in his " Catalogue, 1836," under the provisional 

 name of N. impcrforata. Their form is so peculiar that Mr. Sow- 

 erby has recently grouped them with several others in a new genus, 

 which he calls Globulus. Swainson employs the word Globularia 

 as having a better termination. 



Of the five specimens I have examined, three were mature, and 

 two young. In the oldest, the width of the shell is proportionally 

 greater, and there is a tendency to angularity at about the upper 

 fourth of the last whorl. 



Genus AIWAUROPSIS, Morch. 



Opeeculum pauci-spiral, horny, thin. 



Shell longitudinally oval, thin, smooth, white, not umbilicated, 

 covered witli a light brown epidermis ; spire elevated, suture cana- 

 liculated ; aperture oval, produced in front. 



Amauropsis helicoides. 



Fig. 161. 



Shell ovate, smooth, covered with a dusky yellow colored epidermis ; whorls 

 four, spire channelled at the suture ; umbilicus a mere line. 



Natica canaJicuhtta, Gould, Sillim. Joiirn. xxxviii. 197 (1840) ; Inv. 1st ed. 235, fig. 161. 

 Natica helicoidcs, Johnston, 1835, Tr. N. H. B. — Reeve, figs. 4, 5, 6. 

 Amauropsis helicoides, S rniPSON, Check Lists, 5. 



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

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

 mis ; 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 semi-circular, 

 lip sharp, a little spreading in front, the inner mar- 

 gin nearly a straight line, and overspread with a 

 thick callus ; interior white ; umbilical opening a 

 A helicoides ^^^^'^ ^^^^^ generally none, one side of which is 

 formed by the callus, sometimes altogether con- 

 cealed ; operculum horny, sub-spiral. Length, one and one tenth 

 inches ; breadth, seven tenths of an inch. 



