16 MOLLUSCA FROM THE CRAG. 



2. CYPR/EA AFFINIS. Dujard. Tab. II, fig. 9, a b. 



CYPRJEA AFFINIS. Dujard. M6m. 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-oUongd, transversim striatd ; striis sulco dorsali interruptis, et prope 

 sulcum sub incrassatis ; aperturd angustatd. 



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

 longitudinal furrow ; striae or ridges rather irregular, slightly thickened at their 

 terminations ; aperture elongate. 



Axis, of an inch. 



Locality. Cor. Crag, Button. 



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 irre- 

 gularity 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 speci- 

 mens 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^EA ANGLIC. 8. 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 subcentral ; 

 outer lip thickened and recurved. 



Axis, 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 in 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^A RETUSA. /. Sow. Tab. II, fig. 8, a b. 



CYPR^EA RETUSA. J. Sow. Min. Con. t. 378, fig. 2, 1832. 

 TRIVIA RETUSA. S. Wood. Catalogue 1842. 



T. Testa ovato-globosd, transversim striatd, striis paucis remotis ; sulco dorsali nullo ; 

 aperturd lineatd, submediand. 



Shell ovato-globose, with few transverse striae, not exceeding 8 9 ; spaces between 

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



