GASTEROPODA. 215 
Natica soLuta (Gould). 
Testa parva, globosa, sordidé alba, striis tenuissimis cincta: spira an- 
fractibus quinque ventricosis, superne sub-tabulatis ; sutura profun- 
dissima: apertura semilunaris, angulo postico callo firmato; labro 
acuto, tenui, ad basim incrassato, subeffuso: columella recta, callosa, 
post umbilicum parvum profundum dilatata. 
Natica soluta, Govtp; Proceed. Boston Soc. Nat. Hist., 1. 239. 
July 1847. Expedition Shells, 50. 
SHELL small, thin, nearly globular, dirty white, smooth, but every- 
where decussated by fine lines of growth, and scarcely perceptible 
revolving lines. Spire rounded conical, of five ventricose whorls, 
slightly tabular above and divided by a deep-channeled, delicate su- 
ture: last whorl slightly narrowed, and produced anteriorly. Aper- 
ture semilunar, posteriorly made firm by the angle being filled with 
callus; outer lip thin and sharp, thickened and rounded at base ; colu- 
mella straight, delicate as it passes the small, deep umbilicus, and 
spreading out in callus above. 
Diameter half an inch. 
Probably from the austral coasts of South America. 
A small, nearly globular shell, allied to N. borealis, Gray, and N. 
globosa, King, but distinguished by its deep-channeled suture. 
Figures 257, 257 a, front and back view of the shell. 
AmpuLLACERA Buspyt (Goutp). Hehkz Busbyi, Gray; Ann. and 
Mag. Nat. Hist., vi. 317. ReEEvE; Conch. Syst., u. 164, f. 11. 
Preirrer ; Monog. Helic. Viv., i. 109. 
Concerning this very remarkable shell there is still much doubt. But 
it is very certain that it is not a Helix. It is very difficult to preserve 
the shell entire, because it is covered with a thick, horny, polished 
epidermis, which projects beyond the calcareous portion and warps 
