16 MOLLUSCA FROM THE CRAG. 



2. Cyprjia affinis. Dujard. Tab. II, fig. 9, a — b. 



Cypr/Ea affinis. Dujard. Mem. sur les Conches du Sol en Touraine, Mem. de la Soc. Geol. de 



France, 1837, p. 304, pi. 19, fig. 12. 

 Trivia affinis. >S. Wood. Catalogue 1842. 



C. Testa ovato-oblongd, transversim striata ; striis sulco dorsali interruptis, et prope 

 ■si/Icum sub incrassatis ; aperlurd angustatd. 



Shell ovato- oblong, transversely striated or ridged, interrupted on the back with 

 a longitudinal furrow ; stria? or ridges rather irregular, slightly thickened at their 

 terminations ; aperture elongate. 



Axis, f of an inch. 



Locality. Cor. Crag, Sutton. 



At present I have only two specimens of this species, from the Crag of Suffolk, . 

 and they appear to differ from C. avettana in being of a more elongated form, in the 

 irregularity of the ridges, and in their thickened terminations at the borders of the 

 sulcus. Mr. Lyell has liberally supplied me with a good series of this species from 

 the Touraine beds, which, although presenting much variation among themselves, 

 are always less in size than the British species, and appear to preserve the general 

 character of a naked sulcus. They may, nevertheless, be only varieties of one species, 

 but I have no specimens that will unite the two, and have in consequence kept 

 them distinct, as in all I have hitherto seen a difference may be readily pointed out. 



3. Cypr^a Anglle. S. Wood. Tab. II, fig. 7, a — b. 



Trivia Anglic. S. Wood. Catalogue 1842. 



C. Testa ovato-globosd, striis, transversis paucis, sulco dorsali interruptis, et prope 

 sulcum sub incrassatis ; apertura lineari subcentrali. 



Shell globosely ovate, with a small number of transverse ridges, interrupted by 

 a dorsal sulcus ; ridges slightly thickened at the edge of sulcus ; aperture sub- 

 central ; outer lip thickened and recurved. 



Axis, f of an inch. 



Locality. Red Crag, Sutton. 



This species is rare. It differs from the two preceding ones in having a less 

 number of ridges, and being rather more depressed, with a more orbicular form. The 

 ridges seldom exceed nine in number, and are carried over the sulcus, but appear a 

 little thickened at their edges. The sulcus in the figure is scarcely enough displayed. 



4. Cypr^ea eetusa. /. Sow. Tab. II, fig. 8, a — b. 



CyprjEA retusa. J. Sow. Min. Con. t. 378, fig. 2, 1832. 

 Trivia retusa. S. Wood. Catalogue 1842. 



T. Testa ovato-globosd, transversim striata, striis paucis reviotis ; sulco dorsali nullo ; 

 apertura lineatd, submediand. 



Shell ovato-globose, with few transverse stria?, not exceeding 8 — 9 ; spaces 

 between them broad ; no dorsal sulcus ; aperture subcentral, nearly straight. 



