LAMELLIBRANCHIATA. 121 



nent, incurved, quite anterior. Buccal region slightly swollen. 

 Lunule cordiform, impressed ; a posterior lanceolate lunette is 

 also present. The surface is cancellated with prominent growth 

 laminae, crossed by costae radiating out from the umbo. 



The posterior region behind the shoulder is smooth or with 

 faint shadowy costse. 



Measurements. Antero-posterior diameter, 21 mm. ; dorso- 

 pallial diameter, 12 mm. ; thickness (through both valves), 13 mm. 



Locality. Upware. 



Cardita rottjndata, Pictet and Roux ? 

 (Plate vl, fig. 7). 



Cardita rotundata, Pictet and Roux. Moll. Foss. Geneve, p. 443, 

 pi. xxxiii., f. 6. 



A lower gault species occurring at Folkestone, where it is 

 known by this name ; but it is a longer shell (length equal to 

 breadth) than the Swiss type, and its ribs are fewer and stronger. 



Localities. Upware, Folkestone, Potton. 



S. Europe. Depts. Aube, Yonne, Ardennes, Meuse. 



Range. Neocomian (Upware) and Lower Gault. 



Opis Neocomiensis, D'Orbigny. 

 (Plate vi., fig. 8, a — c.) 



Opis Neocomiensis, D'Orbigny, Pal. Fr. Terr. Cre't., ill., p. 51, 



pi. ccliil, figs. 1 — 5. 

 Opts Desori, De Loriol, Foss. du Mont. Saleve, p. 66, pi. viil, 



f. 4. 

 The shell varies slightly in breadth. There can be little doubt 

 that MM. Pictet and Campiche are justified in their conclusion 

 that 0. Desori (De Loriol) is the same species as the 0. Neocomi- 

 ensis of D'Orbigny. The differences between them are slight, and, 

 according to Pictet and Campiche, depend upon differences in the 

 ages of the specimens. 



Our Upware shells are sometimes corrugated with projecting 

 growth zones. 



