975 



(genus XXX. 



NERITA: 



shell univalve, spiral, gibbous, and flattish 

 underneath; aperture semi-orbicular, with 

 the pillar-lip transverse, truncated, and 

 flattish. 



Sub divisions. '\ 



* Umbilicated. 

 ** Imperforate, with the pillar-lip toothless. 

 *** Imperforate, with the pillar-lip toothed. 



* Umbilicated, 



CANRENA. 1. Shell umbilicated, smooth, and the 

 spire slightly mucroriated, umbilicus gibbous 

 and bifid. 



Nerita Canrena. Lijinaiis Si/st. Nat. p. 1251. Born Mas. 



p. 396. Schroeter Einl. ii. p. 275. Gmelin, p. 3669. 



Schreibcrs Conch, i. p. 313. Maton and Racket, in 



Lin. Trans, viii. p. 223. Montagu Supp. p. 148. 

 Variety A. Chestnut brown, with paler transverse bands, and 

 darker interrupted longitudinal zic-zac stripes. 

 Nerita Canrena. Chemnitz, v. p. 250. t. 186. f. I860 and 



1861. 

 Natica Canrena. Lamarck Syst. des Anim. p. 95. 

 L'Aile de Papillon, ou La Perdrix. Favanne, ii. p. 276. 



t. 11. f. D4. 



t The following of Gnielin's species at p. 3675 appear to me to be unde- 

 serving of notice: N. affinis, N australis, and N. Islandku, N. clathrata, p. 



S675, and N. perversa, p. 3686, are Fossils. 



