GASTEROPODA. 147 



The beautiful specimen from which the figure al)ove referred to was taken is from 

 the Museum of the Philosophical Institution, at York, obligingly sent me by Mr. 

 Charlesworth, for the purpose of being described. I think that there is little doubt of 

 this being identical with the recent Greenland species. Fine striae cover the exterior, 

 which are most visible near the suture and upon the base : and the apex, though not 

 much eroded, has lost its outer coating. 



Sect. /3. OPERCULUM CALCAREOUS. 



11. Natica CLAUSA. Broderip ^wA Sowerby. Tab. XVI, fig. 2, « — h. 

 Natica CLAUSA. Brod. and Sow. Zool. Journ. No. 15, p. 372, 1829. 



— Gray. Zool. of Beechey's Voy. pi. 37, fig. 6, 34, f. 3. 



— Smith. Mem. Wern. Soc. vol. viii, p. 55, pi. 1, fig. 16, 1838. 



— Gould. Invert, of Massachus. p. 238, fig. 167, 1841. 



— S. Wood. Catalogue 1842. 



Natica consolidata. Couthoiiy. Bost. Joura. Nat. Hist, xi, p. 89, pi. 3, fig. 14. 

 — SEPTENTKiONALis. Moller. Ind. Moll. Green, p. 7, 1842. 



N. Testa f/hbosd, imjoerforcdd, leevigaici ; anfractihus quinque ventricosiorihis ; prope 

 sutura7)i jilanidatls ; spird paruni elatd ; aperturd ovatd ; umbilico callo semiorbiculari, 

 complanato, prorsus obtecto. 



Shell globose, imperforate, smooth ; spire slightly elevated, with five convex and 

 rather tumid volutions, somewhat flattened on the upper part ; aperture ovate, left lip 

 with a semiorbicular and flattened callosity, completely covering the umbilicus. 



Axis, 1 inch nearly. 



Localiti/. Red Crag, Sutton. 



Mam. Crag, Bridlington. 



Recent, North of Europe, and Seas of Boreal America. 



This shell is rare as a Red Crag fossil. My cabinet contains but two specimens, 

 which, however, correspond precisely with the figure and description above referred to, 

 and I have no doubt of the identity. My specimens show a few traces of fine striae, 

 where the outer covering has been removed, and there is the impression of its cal- 

 careous lid on both sides of the aperture. It is very common in some of the Swedish 

 beds, as mentioned by Mr. Lyell, and is quoted by Professor E. Forbes, in his 

 ' Report on the Existing Fauna and Flora of the British Isles,' as found at Bridlington, 

 though I have not seen a specimen from that locality. 



