GASTEROPODA. 175 



Ov. patida, which has a non-reflected outer hp. The shell diS'crs from the general 

 character of this genus only in the acuminated form of the upper part of the outer lip, 

 with the fold at the base, as in Bulla, and not above, as in Ovula, and it is not regularly 

 bicanaliculatcd. The striae are most distinct upon the base of the volution, but there 

 are also a few visible at the upper part, whilst, upon the body of the shell, at least in 

 my specimens, it is smooth and glossy.* 



4. Bulla cylindracea. Penn. Tab. XXI, fig. 1, a — c. 



Bulla cylindracea. Pennant. Brit. Zool. vol. iv, t. 70, fig. 85, 17/6. 



— Mont. Test. Brit. p. 221, t. 7, fig. 2, 1802. 



— Don. Brit. Shells, vol. iv, t. 120, fig. 2, 1805. 

 Bulla convoluta. Broc. Coq. foss. Subapenu. t. i, fig. 7, 1814. 



— J. Sow. Mill. Conch, t. 464, fig. 1, 1824. 

 VoLVARiA CYLINDRICA. Brovon. lUust. Brit. Conch, pi. 38, fig. 36-37, 1827. 

 Bulla convoluta. Grat. Not. sur la Fam. des Bull. pi. 3, fig. 37, 1837. 



— Phil. En. Moll. Sic. vol. ii, p. 97, 1844. 



— Nyst. Coq. foss. de Belg. p. 454, pi. 39, fig. 6, 1844. 

 Bulla cylindracea. S. Wood. Illust. in Mag. Nat. Hist. pi. 7, fig. 8, 1839. 

 Cylindrella alba. Swains. Treat, on Malac. p. 326, fig. 94 b, 1840. 

 Cylichna cylindracea. Loven. Ind. Moll. Scand p. 10, 1846. 



B. Testa cylindricd crassd ; tenuissime striata ; aperturd lineari, versus basim parum 

 dilatatd ; vertice triincato, depresso ; spird occulta ; columelld obtuse unipUcatd. 



Shell elongato-cylindrical, convolute, upon a nearly horizontal axis, covered with 

 fine, transverse, regular strise ; aperture linear, dilated at the base, with an obtuse 

 fold upon the columella ; vertex depressed, concave, with a hidden spire. 



Jxis, I of an inch ; diameter, | its length. 



Locality. Cor. Crag, Sutton. 



Red Crag, Sutton. Recent, British Seas. 



This species is very abundant at one locality in the Coralline beds, but is very rare 

 as a Red Crag shell. The volution being nearly horizontal, the outer lip is carried 

 above the spire, and there is a little inflection of the shell at that part which covers 

 what would otherwise be a perforation ; a small hole may be occasionally seen, but it 

 is generally closed. 



Among my Crag fossils, as well as among my recent specimens, are indi\-iduals 

 both smooth and striated, but the condition of the latter is, I believe, dependent upon 

 the state of preservation of the exterior. In a recent state it is covered by an epidermis, 

 and then the strise are well seen. In the description by the above-quoted authors, 



* Since the above was written I have seen the recent shell from the !\Iediterranean, which is rather 

 more cylindrical, less regularly fusiform, and the pointed portion of the upper lip less acuminated, with 

 a few faint striee upon the base ; such differences are probably only the result of locality, and cannot be 

 considered specific. 



