74 MOLLUSCA FROM THE CRAG. 



SECT. HOLOSTOMATA. FLEM. 



TURRITELLA,* Lam. 1815. 

 TURBO (spec.) Linn. 



Gen. Char. Shell elongate and turriculate, generally thick and strong, tapering to 

 an acute apex, volutions numerous ; aperture entire, subcircular, or slightly quadrate ; 

 outer lip thin and sharp, somewhat sinuous ; operculum corneous and spiral. 



Shells of this genus are generally well distinguished from those of any other, 

 excepting it be perhaps some aberrant forms of Cerithium ; a more or less emarginate 

 base distinguishes the latter genus, although in some species this character is very 

 imperfectly displayed. 



As a genus this is not restricted to any climate, some species being found within 

 the tropics, while others are inhabitants of the coasts of Greenland and Scandinavia, 

 and, according to Mr. J. Sowerby, it appears in the Protozoic rocks (vide Sil. Syst.) ; 

 these shells, however, resemble so much in form those of Murchisonia, that unless the 

 specimens are very perfect it would be difficult to distinguish them. There is, 

 however, a well-marked species from the Greensand formation. (Vide Min. Con. t. 565.) 



1. TURRITELLA COMMUNIS. Eisso. Tab. IX, fig. 9, ab. 

 TURBO TEREBRA. Mont. Test. Brit. p. 293, 1803. 



TURRITELLA COMMUNIS. Risso. Hist. Nat. des princ. Prod, de 1'Europe, iv, p. 106, fig. 37, 1826. 

 TEREBRA. J. Sow. Min. Conch, t. 565, fig. 3, 1827. 



Woodward. Geol. of Norf. p. 44, 1833. 

 LINN.EI. Desk. Exp. de Moree, torn, iii, p. 146. 



Dujard. Me"m. de la Soc. Geol. de France, p. 287, 1837. 

 TEREBRA. S. Wood. Catalogue 1842. 

 COMMUNIS. Phil. En. Moll. Sic. vol. ii, p. 160, 1844. 

 PLEBEIA. Say. Lyell in Proc. of Geol. Soc. 1845, vol. iv, pt. 3, p. 554. 



T. Testa turrita, subulatd; anfractibus convexiusculis ; transversim lineatis; lineis 8 10, 

 elevatis acutimculis; cequalibus, vel intequalibus, cinctis. 



Shell turriculate and tapering, with very slightly convex volutions ; covered with 

 8 10 fine ridges, sometimes equally distributed, at others rather irregular in size and 

 number ; outer lip sinuous. 



Axis, 1} inch. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bramerton and Bridlington. Recent, British Seas. 



This shell is given by Professor E. Forbes, in his ( Report upon the Existing Fauna 

 and Flora of the British Isles,' as a Coralline Crag species. I have no specimen from that 

 formation. It is, however, very probable it may have lived in the seas which deposited 

 the Coralline Crag, having been given as a Touraine species by M. Dujardin, and as an 



* Etym. From Turris, a tower. 



