218 NATICID.E. 



It is the N. pusilla of Gould, but not of the original 

 describe!*, Say, which latter species is oval and very much 

 smaller than ours, having a calcareous operculum and 

 the umbilicus completely closed by a pad. N. nana 

 of Moller appears to differ from Say's shell merely in 

 having a horny operculum. Our shell is the N. livida 

 of Bean, N. borealis of Gray, N. Gouldii of Philippi, 

 N. alba and N. lactea of Loven's MS. according to 

 Philippi, and N. bulbosa of Reeve; probably also the 

 N. Beverlii of Leach, being one of the " invertebrate ani- 

 mals discovered by HisMajesty's Ship Isabella " [!] , and 

 described in ' Sir John Ross's Voyage to Baffin's Bay/ 

 It is difficult to decide, from the too short diagnosis given 

 by Broderip and Sowerby, whether their N. pallida is 

 the present species or N. Islandica. Morch placed N. 

 Groenlandica in the genus Mamma of Klein, an olla 

 podrida of Nerita, Natica, Dolium, Buccinum, Turbo, and 

 Purpura. We cannot say of such systematists, " Et 

 quo antiquius, eo melius." 



3. N. sor'dida*, Philippi. 



N. sordida, Phil. Moll. Sic. ii. p. 139, t. xsir. f. 15 ; F. & H". iii. p. 334, 

 pi. c. f. 5, 8, and (animal) pi. PP. f. 3. 



Body fleshcolour or pale tawny : snout strong and very large, 

 whitish except at the extremity, which is reddish -brown : ten- 

 tacles having fine and tapering points : eyes, none perceptible : 

 foot enormous, very slimy, truncated or cloven in front, and 

 rounded behind. 



Shell globose, inclining to oval, thick and solid, opaque, 

 somewhat glossy : sculpture, minute, irregular, fiexuous, and 

 slight spiral lines, which are stronger or more conspicuous 

 below the suture of the body- whorl and on the base : colour 

 buff, passing into chestnut : epidermis thin, of a lighter shade 

 than the main colour of the shell : spire short, slightly pro- 

 minent ; apex abraded or decorticated : ivhorls 5-6, tumid 



* Dirt-coloured. 



