GASTEROPODA. 15 



cxliibit this feature, even if it originally existed ; the })lications of growth are also very 

 large, so that in the latter volntions they render the carina) distinctly nodulous ; in 

 C. vittata the carinac are but slightly modified by this cause. 



D'Orbigny, ' Prodrome,' has suggested that Ncrinan mprajurensis, D'Archiac, may 

 be C. vitfata ; but, judging from the figure of D'Archiac, N. sitprajuremis is more slender, 

 with the volutions mnch more numerous and more narrow, the sutures are also desti- 

 tute of that deeply indented figure which is so conspicuous in our Cornbrash shell. 

 The general resemblance which C. vittata bears to some examples of the genus Nerinsea 

 has led me to make a longitudinal section of it, and thus to ascertain with certainty that 

 it cannot be assigned to that genus. 



Gcohfjical Position and Locality. The Cornbrash of Scarborough and Gristhorp ; it is 

 not rare, but is very difficult to disengage from the hard limestone. 



KiLVERTiA, Gen. Nov. 



The views expressed on Cerifhitan strangulatum, p. 8, suggesting the propriety of 

 erecting a new genus for the reception of that and other allied forms, have subsequently 

 been strengthened by the examination of well-preserved specimens from the Forest 

 Marble of Somerset and Wilts, in the collection of W. Walton, Esq., of Bath. I have 

 now, therefore, no hesitation in proposing for these the new generic appellation Kilvertia, 

 which will be found described in the Addenda. 



Kilvertia constricta, Lye. Tab. XLIV, fig. 8. 



Testa parva turrita, elongata, anfractibus (8) superne planalis, in/erne ventricosis, suturis 

 bene distinctis, lineis transversalibus et longitiidinalibus, delicatissimis, cancellatis ; apertura 

 sxborbicnlari depressa, incrassato. 



The height of each volution is about equal to half its opposite measurement, the first 

 encircling line beneath the suture is rather more prominent than the others; altogether 

 there are six ; their size and distances correspond nearly with the lines by which they are 

 decussated ; the aperture is imperfect at the outer lip, there is no umbilical chink. 



Geological Position and Locality. A minute univalve, obtained by crushing shelly 

 portions of the Great Oolite of Minchinhampton Common ; Mr. Witchell has also kindly 

 forwarded a specimen obtained by him at the same locality, and in the same manner. 



