104 MOLLUSCA FROM THE CRAG. 



with a large and prominent obtuse varix, and there are about eight denticulations 

 within the outer lip. 



This may possibly be R. Montagui, Payr. (p. 111, t. 5, f. 13-14), but our shell 

 appears to be less in size, and less ventricose. The elevated transverse ridges give an 

 apparent canal at the suture, and the outer lip is continuous with the inner one ; at the 

 base of the inner lip or columella the shell is slightly reflected. A shell somewhat 

 resembling this species, but larger, is not very uncommon in the London clay, at 

 Barton; it is thickened within the outer lip, but has not the denticulations characteristic 

 of the Crag shell. Our figure represents the striae as rather too fine and too numerous. 



7. RISSOA PULCHELLA (?). Phil Tab. XI, fig, 9, a b. 



RISSOA PULCHELLA. Phil. En. Moll. Sic. 1836, p. 155, t. 10, fig. 12. 



R. Testa ovato-conicd, ventricosd, inflatd, crassd, subperforatd; anfractibus quinque, con- 

 vexis, tumidis, longitudinaliter costulatis ; costulis circiter quatuordecim, in anfractu ultimo 

 dimidiatis ; aperturd ovatd, spiram subcequante ; labro incrassato, intus denticulate (?). 



Shell ovato-conoidal, ventricose, thick, and strong, with five convex volutions 

 longitudinally costated ; costae about fourteen, disappearing on the lower half of the body 

 whorl, with an ovate aperture, and a thickened outer lip, denticulated (?) within. 



Axis, ~ of an inch. 



Locality. Red Crag, Sutton and Kesgrave. ? Recent, Mediterranean. 



My cabinet contains five specimens of what appears to be the same as the 

 Mediterranean shell ; they have the inflated form and numerous ribs of M. Philippi's 

 figure, but there are the remains of striae upon the base of our shell, and traces of 

 denticulations within the aperture, which do not appear to exist in the former. It is 

 larger and more ventricose than any of my specimens of R. semicostata, yet it is possible 

 it may be only a variety. The costae in our figure are rather too numerous, and the 

 volutions scarcely tumid enough. 



8. RISSOA CONFINIS. S. Wood. Tab. XI, fig. 6, a b. 



ttissoA CONFINIS. S. Wood. Catalogue 1842. 



R. Testa ovato-conicd, subperforatd crassd; apice obtuso ; anfractibus quinque, 

 convexiusculis ; suturis profundis, longitudinaliter costatis ; costis rectiusculis, elevatis, in 

 anfractu ultimo 9 12, transversim striatis, aut sulcatis ; aperturd subrotundd ; labro 

 extus incrassato, intus dentato ; labio moo reflexo, umbilico parvo. 



Shell small, ovato-conoidal, perforate, thick and strong, with a rather obtuse apex ; 

 volutions five, convex; suture distinct and deep, longitudinally costated ; costae 9 12, 

 nearly erect, elevated, covered with depressed transverse striae ; aperture suborbicular ; 

 outer lip thickened, dentated within ; peristome continuous ; the left lip slightly reflected, 

 partly covering a small umbilicus. 



Axis, TO of an inch. 



Locality. Cor. Crag, Sutton. 



