GASTEROPODA. 143 



Longest diameter, f of an inch. 



Locality. Red Crag, Sutton. Recent, Mediterranean. 



A few specimens of this shell in my cabinet appear to resemble the recent Medi- 

 terranean species in the peculiar form of the reflected and thickened portion of the 

 lower part of the left lip which extends partly over what would be a small umbilicus, but 

 the specimens are much altered and decorticated, thereby causing a greater opening 

 at that part of the shell. I have considered this as different from the young of 

 N. catenoides on account of a greater number of volutions in shells of the same size ; 

 a specimen of this species having five volutions, with a diameter scarcely exceeding a 

 third of that of N. catenoides, which has never more than six. It must, however, for 

 the present, be considered doubtful. 



4. NATICA PROXIMA. 8. Wood. Tab. XVI, fig. 4, a b. 



NATICA PROXIMA. S. Wood. Catalogue 1842. 



N. Testa subglobosd, obliqud, lavigatd, politd ; anfractibus quinque subdepressis ; spird 

 breviusculd ; aperturd semilunari ; mnbilico lato, labio cattoso. 



Shell subglobose, smooth, and glossy ; volutions about five, oblique, and rather 

 depressed, spire short ; aperture hemispherical, with an open and deep umbilicus, 

 modified by the callosity of the left lip. 



Longed diameter, 1 inch. 



Locality. Cor. Crag, Ramsholt. 



My cabinet contains but a few specimens of what I have presumed to be a distinct 

 species. The umbilicus is large and deep, somewhat reduced above by the callosity of 

 the lower portion of the left lip, and there is a peculiar flatness upon the columella, 

 unlike the line produced by the pressure of a testaceous operculum. Some faint lines 

 of striae are visible when the outer covering is removed, particularly near the suture. 

 It differs from N. varians in having a much less elevated spire, a less depressed 

 suture, and a rather larger callosity. It somewhat resembles N. hemiclausa, but 

 that species is rather more depressed in the volutions, and has its umbilicus entirely 

 closed. 



5. NATICA VARIANS. Dujard. Tab. XVI, fig. 6, a b. 



NATICA VA.EIANS. Dujard. Mem. de la Soc. Geol. de France, torn, xi, pt. 2, p. 281, pi. 19, fig. 6, 1837. 



HEMICLAUSA(?). Nyst. Coq. foss. de Belg. p. 446, pi. 38, fig. 15, 1844. 



ELEVATA. S. Wood. Catalogue 1842. 



N. Testa ovato-conicd, crassd, l&vigatd, politd, spird elevatd ; anfractibus sex obliquis ; 

 aperturd seminulatd, labio cattoso ; umbilico magno aperto, prof undo. 



Shell ovato-conical, thick, strong, smooth, and glossy, with an elevated spire, and 

 about six oblique or sloping volutions ; umbilicus rather large, open and deep ; left 

 lip callous. 



