GASTEROPODA. 145 



7. NATICA CIRRIFORMIS. /. Sow. Tab. XVI, fig. 7, a b. 



NATICA CIRRLFORMIS. J. Sow. Min. Conch, t. 479, fig. 1. 

 S. Wood. Catalogue 1842. 



Morris. Catalogue of Brit. Fossils, p. 152, 1843. 

 Nyst. Coq. foss. de Belg. p. 444, pi. 39, fig. 1, 1844. 



N. Testa fflobosd, crassd, lavigatd ; anfractibus sex, convexis; spird depressd ; aper- 

 turd semilunatd; labio in/erne cattoso ; umbilico lato, pro/undo. 



Shell globose, thick, smooth; volutions convex, tumid; spire slightly elevated; 

 umbilicus wide and deep, with a broad sinus in the left lip, callous at the lower part ; 

 aperture semilunate. 



Longest diameter, 1 \ inch. 



Locality. Cor. Crag, Ramsholt. 



I have not seen this species from the Red Crag ; and specimens of it from the 

 Coralline beds are generally in a decorticated state. Its distinguishing character is 

 the callosity at the lower part of a large umbilicus., the upper side of which has a 

 distinct ridge when the shell is well preserved, the left lip being, as it were, separated 

 in the middle by a deep and broad canal ; unlike N. mullipunctata, the ridge is on 

 the lower part of the umbilicus, and not in the middle ; the volutions expand, and are 

 somewhat compressed above and below, forming a large and wide umbilicus. 



8. NATICA HELICOTDES. Johnston. Tab. XVI, fig. 3, a b. 



NATICA HELICOIDES. Johnston. Hist, of the Berwickshire Nat. Hist. Club, 1834. 

 Lyell. In Mag. Nat. Hist. 1839. 



CANALICULATA. Gould. Report on the Inv. of Massachusetts, p. 235, fig. 161, 1841. 



HELICOIDES. S. Wood. Catalogue 1842. 



Morris. Catalogue of Brit. Fossils, p. 153, 1843. 



N. Testa ovatd, crassd, l&vigatd (?) ; spird elevatd ; anfractibus guatuor vel quinque 

 convexis; suturisprofundis; aperturd ovatd ; umbilico tecto. 



Shell ovate, thick, and smooth (?) ; spire elevated ; volutions four or five, convex, 

 with a deep or canaliculated suture ; aperture ovate, scarcely oblique, and without an 

 umbilicus. 



Axis, 1 inch nearly. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bramerton and Bridlington. 



Recent, North Seas and Coast of Massachusetts. 



This shell is rare in the Red Crag, though I believe it is not so in the Mamma- 

 liferous formation. It was given as an extinct species in the list of Mammaliferous 

 Crag Shells, published in the ' Mag. Nat. Hist. 1839', the joint production of Mr. Lyell, 

 Mr. G. Sowerby and myself, as we were not then aware of its existence as a recent 

 shell. We have since been able to compare the recent and fossil shells, and have no 



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