126 INVERTEDRATA. 



and a fourth tooth, which starts under the umbo, runs obliquely 

 along the posterior cardinal margin. 



Localities. Upware, Atherfield, I.W. V 



PANOP^A PLICATA, Sowerby. 



Mya plicata, Sowerby. Min. Con. pi. ccccxix., f. 3. 

 Localities. Upware, Atherfield, Sandown, Speeton, Sandgate, 

 Hythe. 



N. Europe. Bredenbeck, Hils Thon. 



S. Europe. Perte du Ehone, St Croix, Vassy. 



PANOP^A GURGITIS, D'Orbigny. 

 Panopcea plicata, Goldfuss., Pet. Germ., p. 274, pi. CLVIII., f. 5 



(non Sby.). 

 Panopcea gurgitis, D'Orb., Pal. Fr. Terr. Crti., ill., p. 343, 



pi. CCCLXI., f. 1, 2, 



Localities. Upware (Coll. Mr J. F. Walker). 

 S. Europe. Dept. Var. (Cenoman.) 



?THRACIA or TELLINA. 

 (Plate vi., fig. 14). 



A doubtful shell, of which only two specimens have been 

 discovered at Upware. It bears much resemblance to the figures of 

 Thracia Couloni, Pictet and Renevier, Pal. Suisse, Terr. Aptien, 

 p. 66, pi. vii., f. 4. 



Locality. Upware. 



BORING SHELLS. 



Lithophagous bivalves lived in great abundance at the time 

 when the Ironsand and Phosphatic Series was being deposited, so 

 that commonly the phosphatic nodules are studded with the open- 

 ings of their small burrows, which are usually about so big as to 

 admit easily a large pin's head. Some shells collected from these 

 burrows shew that they were made by small Modiola and Arca-Yike 

 bivalves (Lithodomus and ? Saxicava). 



