GASTEROPODA. 39 



MuREx, Linn. 1767. 

 Chicokeus. Montf. 1810. 

 Triton. Flem. 1828. 

 Phyllonotus. Swains. 1840. 

 Pteronotus. ... 



MnRICIDEA. ... 



Gen. Char. Shell turreted, elongato-ovate, or fusiform ; generally ventricose, thick, 

 and strong ; externally rugose, with three or more longitudinally branched, spinous, 

 fringed, or reflected fimbrise, more or less elevated, foliaceous, or tuberculous ; spire 

 prominent and acute ; aperture ovate, terminating at the base in a partly-closed canal ; 

 operculum corneous, concentricall)r formed and pointed. 



The shells of this genus have three or more divisions of the volution, formed by an 

 extended or fimbriated margin of the outer lip, at chifcrent periods of growth, by which 

 means the shell is elegantly ornamented externally ; and among the recent portion of 

 the genus are some of Nature's most beautiful productions. It differs from Ranella, 

 which has only a bipartite division of the whorl, and in Triton the varices are more 

 irregular, and not fimbriated. This genus is found in the Oolite, and twenty species are 

 enumerated as belonging to the Paris basin. M. Michelotti mentions forty-four from 

 the Subapennine beds. Only two species have as yet been found in the Crag, and 

 those are by no means numerous in individuals. 



1. MUREX ERIN ACE us, Lm7l. 



MuREX ERiNACEUs. LhiH. Syst. Nat. p. 1216. 



— Pennant. Brit. Zool. iv, t. "6, fig. 95, 1776. 



— Brocchi. Conch, foss. Subap. p. 391, pi. 7, fig. 11, 1814. 



— Dujardin. Mem. de la Soc. Geol. de France, 1837, p. 295. 



— S. Wood. Catalogue 1842. 

 Triton erinaceus. Flem. Brit. An. p. 356, 1828. 



M. Testa ovato-fusiformi, transversim sulcato-rugosd, quadrifariam ad septifariam 

 varicosd ; varicihm elevafis ; aperturd ovatd ; canali clauso recurvd. 



Shell subfusiform, ovate ; roughly sulcated transversely with from four to seven 

 rather obtuse varices ; aperture ovate, with a slightly recurved canal, which is out- 

 wardly closed in the adult state. 



Locality. Mam. Crag, Bramerton. Recent, Britain. 



One specimen of this species was found some years since by Mr. J. Wigham, of 

 Norwich, and sent to Mr. Lyell, ■with whom I examined it, and we were both satisfied 

 of its identity with the well-known recent shell. Upon application to the o-mier of 

 the specimen for the privilege of having it figured, he informed me it had been sent 

 to Mr. Green, of Bacton, for the purpose of publication, and unfortunately lost. 



