GASTEROPODA. 



7. Natica cirriformis. /. Sow. Tab. XVI, fig. 7, a — b. 



Natica ciHRifORMis. J. Sow. Miu. Conch, t. 479, fig. 1. 



— S. Wood. Catalogue 1842. 



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



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



N. Testa ghhosd, crassd, Itsvif/atd ; anfradibus sex, convewis ; spird depressd ; aper- 

 turd semilunatd; labia inferne calloso ; umbilico lata, prof 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 ; 

 ajjerture semilunate. 



Longest diameter, \\ 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. midtijmnctata, 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 umbihcus. 



8. Natica helicoides. Johnston. Tab. XVI, fig. 3, a — b. 



Natica helicoides. Johnston. Hist, of the Berwickshire Nat. Hist. Club, 1834. 



— — Lyell. In Mag. Nat. Hist. 1839. 



— CANALICDLATA. Gotild. Report on the Inv. of Massachusetts, p. 235, fig. 161, 1841. 



— HELICOIDES. S. Wood. Catalogue 1842. 



— — Morris. Catalogue of Brit. FossOs, p. 153, 1843. 



K Testa ovatd, crassd, Iceviffatd Q) ; spird elevatd ; anfractibus quatuor vel qiiinque 

 convexis ; sidurisprofundis ; aperturd ovatd ; umbilico tecto. 



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

 with a deep or canaliculatcd 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 1 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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