GASTEROPODA. 143 



Longest diameter, f- of an inch. 



Locality. Red Crag, Sntton. Recent, Mediterranean. 



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

 Mediterranean 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. S. Wood. Tab. XVI, fig. 4, a — b. 



Natica proxima. S. Wood. Catalogue 1842. 



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

 breviusculd ; aperturd semilunar i ; umbilico la to, labio calloso. 



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. 



Longest diameter, 1 inch. 



Localitg. 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 strice are visible when the outer covering is removed, par- 

 ticularly near the suture. It differs from JY. 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 varians. 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. 44G, pi. 38, fig. 15, 1844. 



— elevata. S. Wood. Catalogue 1842. 



N. Testa ovalo-conicd, crassd, lavigatd, politd, spird, elevata ; anfractibus sex obliquis ; 

 aperturd seminulatd, labio calloso ; 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. 



