GASTEROPODA. 55 



volution, and the lip curves elegantly from the sinus. The only difference I can 

 observe in the shells from the two different formations is in the arrangement of the 

 transverse striae, which are broader and more regular in the Crag shell than they 

 are upon the Barton shells, but living under altered conditions would in all 

 probability modify these appearances. 



5. Pleurotoma poeeecta. S. Wood. Tab. VII, fig. 1, a — b. 



Pleukotoma pokrecta. S. Wood. Catalogue 1842. 



PI. Testa por recta, elongato-fusiformi ; spird turritd, apice acuto ; anfractibus 9 — 10, 

 parum convexis, subangulatis, transversim tenuissime striatis ; in medio nodulosis ; canali 

 longiusculd recta. 



Shell elongato-fusiform, with an elevated spire and acute apex; volutions 9 — 10, 

 slightly convex, finely striated transversely, and furnished in the middle of each 

 whorl with one row of obtuse, ovate nodules ; aperture ovate ; canal elongated. 



Axis, \\ of an inch. 



Locality. Cor. Crag, Gedgrave. 



When my Catalogue was drawn up I possessed but one mutilated specimen of this 

 species. I have, however, obtained another since that time, and with three more 

 belonging to H. Daniel, Esq., I am enabled to define its characters. The length of the 

 aperture, including the canal, exceeds two fifths of the entire length of the shell, but 

 in many species that character is liable to great variation, and is not much to be 

 depended upon. The nodules are obtuse, oblique, and placed in the centre of the 

 whorls ; they are produced by the reflected edge of the lower part of the sinus in 

 the outer lip, which being thickened externally at different periods, leaves perma- 

 nent nodules which ornament the exterior. They are about ten in the penultimate 

 whorl, but become nearly obsolete on the older part of the shell. It is covered with 

 very fine impressed stria?, the spaces between them being broad, flat, smooth, and 

 glossy, differing in that respect from the rough, elevated strias upon PI. nodularia, 

 Desh. (Coq. foss. de Par. p. 493, t. 66, f. 23 — 25). In other respects it much re- 

 sembles that shell. It might perhaps be considered as PI. noduliferum, Phil. (En. 

 Moll. Sic. vol. ii, p. 173, t. 26, f. 16), only that he has described that shell as 

 " lasvissima," and his figure does not appear quite so tapering as the one from the 

 Crag, and it has also a shorter canal. When, hereafter, the shells are compared, 

 they may prove the same, but not knowing the Sicilian species I have left the Crag 

 shell with its provisional name. A shell in Mr. Ly ell's cabinet from Touraine is 

 probably identical with the Crag specimens. 



6. Pleueotoma nodulosa (?). Desh. 



Pleurotoma nodulosa (?). Desk. Coq. foss. des Env. de Paris, pi. 65, fig. 11-14. 



A few fragments resembling this Eocene species are in my cabinet, but they are 

 too imperfect for figuring or fair description. My best specimens appear to have 



