GASTEROPODA. 85 



Stomatia? (Megastoma), Buvignieri. Plate IX, fig. 32, 32 a. 



S. Testa semiglobosd; spird parvd, depressd; anfractu ultimo transversim costulato, et 

 in medio carinato, carina acuta, elatd, costis longitudinalibus densis, lineis tenuissimis 

 impressis notatis; aperturd magna semilunari; labio externo fisso ? 



Shell semiglobose ; spire depressed ; last whorl with a mesial, elevated, acute carina, 

 crossed by longitudinal, narrow, elevated ribs — the ribs being impressed by fine encircling, 

 transverse lines ; aperture very large ; outer lip slightly notched. The shell above the 

 carina is flattened ; the ribs, which are perfectly regular, pass over the carina, and beneath 

 are decussated by fine transverse lines. 



Locality. This rare shell, which attains the size of a small bean, has only been found 

 in the soft oolite beneath the planking on Minchinhampton Common. 



We have dedicated this species to M. Buvignier, who has figured and described some 

 apparently congeneric forms under the name of Stomatella carinata and S.funata. (See 

 'Mem. Soc. Phil. Verdun,' 1843, p. 19, t. 5, f. 27—30.) 



Family — Fissurellid^. 

 Fissurella, Lam. 1801. 



Fissureli/us, Montfort, 1810. 



Shell conical, base entirely open, orbicular or oval ; apex central or subcentral, having 

 a foramen of an oval figure, central, or near to the anterior or shorter side ; surface usually 

 cancellated, or ornamented with ribs and lines ; margin generally thickened ; muscular 

 impression nearly continuous. 



Fissurella acuta, Desl. Plate VIII, fig. 5, ha — c. 



Fissurella acuta, Deslongchamps, 1842. Mem. Soc. Linn, de Normandie, torn, vii, 



pi. 7, figs. 22—24. 

 Rimula — If Orb. 1850. Prod. Paleont., p. 303. 



F. Testa conicd, altd; bast subcirculari; apice acuto, subcentrali; foramine subapiciali, 

 antice versato, superne rotundato, in/erne rimd angustd producto, striis longitudinalibus 

 parvis crebris, aliis transversis testam decussantibus. (Deslong.) 



Shell conical, elevated, nearly circular ; apex acute, nearly central ; foramen a little 

 anterior to the apex, rounded above, narrow below; striae longitudinal, small, closely- 

 arranged, crossed by others, transverse and less prominent. Height 3 lines, base 3 lines. 



12 



