182 MOLLUSCA FROM THE CRAG. 



4. Bdlljia ventrosa. S. Wood. Tab. XXI, fig. 11, a — c. 



Bulla ventrosa. S. Wood. Illust. in Mag. Nat. Hist. p. 462, pi. 7, fig. 5, 1839. 

 — S. Wood. Catalogue 1842. 



B. Testa pusilld, crassd, ventrosa, ovato-globosd ; spird occulta; anfractibus paucis, 

 ohliquis, laxe convolutis, svperne vix coarctatis ; striatis ; striis divergentibus, excavato- 

 punctatis ; aperturd ovali, in/erne patente, dilatatd ; labio prominente, pone umbilicato. 



Shell small, strong, ventricose, ovato-globose ; spire concealed by the elevation 

 of the outer lip ; volutions few, slightly enrolled, covered externally, with numerous 

 regular, punctured, and diverging striae ; body of the whorl slightly contracted on 

 the upper half ; aperture ovate, somewhat contracted above, expanded below ; inner 

 lip prominent, slightly reflected, with a small umbilicus behind it. 



Axis, y of an inch ; diameter, ^. 



Locality. Cor. Crag, Sutton. 



I have obtained only a few specimens of this shell. It somewhat resembles a 

 minute B. lignaria, but it has an umbilicus, and is otherwise distinct. My specimens 

 appear to have punctured lines, and not chain -like striae on the exterior ; but they 

 may, perhaps, be in an altered condition. This may possibly be Bulla zonata, Turt. 

 Mag. Nat. Hist. 1834, p. 352, but the crown of our shell can scarcely be said to be 

 umbilicated ; the outer lip is deeply cleft or sinuated, and disconnected up to the 

 vertex ; and the replication of the inner lip forms a distinct umbilicus. There is a 

 deep muscular impression running nearly parallel with the outer lip, which is 

 regular and continuous the whole length of the shell. 



Oed. CYCLOBRANCHIATA. Cuv. 

 Patella. Linnaus. 1758. 



Gen. Char. Shell conical, clypeiform, with an oblong or ovate base ; apex or 

 vertex subcentral, always more or less on the anterior portion ; generally rayed, 

 striated, or costated, with a crenulated margin, occasionally smooth ; muscular 

 impression, a ligulate band surrounding the interior, about half way up, open in 

 front for the head of the animal. 



Animals of this genus differ from the fissured and keyhole limpets in having the 

 branchiae on the outer edge under the margin, and have, in consequence, been 

 placed in a different order. When living, the edge of the shell is generally slightly 

 raised from the rock, to admit the water to the branchiae, and the blade of a knife 

 can easily be passed under the margin of the shell, if undisturbed; but when 



