334 NATICIDiE. 



it appeared first during the epoch of the red crag', and 

 lived throuoh tliat of the northern drift. 



N. soRDiDA, Phihppi. 



Large, subglobular, uniform chestnut ; body not attenuated 

 above ; spire much depressed ; umbilicus open, smooth, edged 

 with a coloured band ; enamel of the inner lip chocolate. 



Plate C. fig. 5, 8, and (Animal) Plate P P. fig. 3. 



\atica fulvu, Thompson, Ann. Nat. Hist. vol. v. p. 99 (no description). 



„ sordida, PiiiLiPPi, (not Swainson) Moll. Sicil. vol. ii. p. 139, pi. 24, 



f. 15. — Thompson, Ann. Nat. Hist, new ser. vol. iii. p. 352 



(no description). 

 „ allied to monilifera, Forbes, Ann. Nat. Hist. vol. xiv. p. 413. 

 „ plu7nbea, Philippi (not Lamarck), None Conch, vol. i. p. 15, pi. 1, f. 5. 

 „ proxima, SearlesWood, Crag Moll. vol. i. p. 143, pi. 10, f. 4, fossil. 



As the N. sordida of Swainson's Zoological Illusti-ations 

 is specifically identical with the plumbea of Lamarck, we 

 are enabled to retain that appellation foi' the present 

 species ; had not the name proxima been applied, under 

 the supposition that the species had never been previously 

 described, we should have held it right to have adopted it 

 in preference. 



This shell partaking of the characters of both the preced- 

 ing species, when large approaches more near!}' to monili- 

 fera^ when small to nitida. A long suite of examples in the 

 collection of Mr. M'Andrew forbids the annexation of it to 

 either. Our description of nitida will for the most part 

 apply to it ; its shape, however, is a little broader, and not 

 quite so oblique, and the body is not peculiarly attenuated 

 above. The spire is more depressed than in the species we 

 are comparing it with, and tlie whorls are consequently less 

 rounded, and often a little flattened horizontally above. 



