84 



but are easily distinguished from them by the widening at their base> 

 and by the columella being smooth. 



I do not know of any English fossil of this genus; but they appear to 

 be frequent in the environs of France ; since Larnarck enumerates and 

 describes twelve species : M. costellata, M. lactea, M. marginata, M. hor- 

 dacea, M. canicularis, M. corrugata, M. semiplacata, M. nitida, M. semi- 

 striata, M. cochlearella, M.fragilis, and M. dubia. 



M. marginata, represented PL V. Fig. 9, judging from the specimens 

 in my possession, exists in a very unimpaired state. 



LI II. Auricula. An ovate or oblong pyramidal univalve, with the 

 spire extruded : the opening entire, oblong, and narrowed upwards ; 

 the columella plicated, with different plicae in the opposite lip. 



Those volutes of Linnaeus, which are not notched at their base, Bru- 

 guiere, without considering their plicae, placed under the genus Buli- 

 mus. Lamarck has, with great propriety, placed those shells whose 

 openings arfe entire, but whose columelltfe are plicated* under this genus, 

 Auricula. 



One of the most interesting shells of this genus, is Auricula ringens, 

 Lam. acutely ovate, rather turgid, transversely ribbed, with minute 

 longitudinal striae, the edges of the opening thick and bordered, the 

 right lip dentated, and the columella with three plicae. This shell is 

 found at Grignon and in the neighbourhood of Bourdeaux. The spe- 

 cimen which is represented Plate V. Fig. 4, and which appears to be 

 A. ringens, is nearly transparent. It is one of those extraordinary sili- 

 cious fossils which are yielded by the Blackdown whetstone-pits, and for 

 a supply of which I am under great obligations to R. H. Clarke, Esq. 

 of Bridwell, and the Rev. J. R. Cleeve, of Kentisbeare, who have 

 kindly assisted me with the interesting fossils of their respective neigh- 

 bourhoods. 



LIV. Volvaria. A cylindrical convoluted univalve : the spire not 

 extruded : the opening narrow, the length of the shell : the columella 

 plicated at its base. 



