318 



CRETACEOUS LAMELLIBRANCHIA. 



pass into forms with indistinct folds like the type of I. Cuvieri, Sowerby (Fig. 

 73), and in some cases the folds disappear altogether. 



..A 



#; 



x 



WMto 



Fig. 76. — Inoceramus Lamarcki var. Cuvieri, Sow. The type of Inoceramus latus, Mantell, ' Foss. S. Downs,' 

 p. 216, pi. xxvii, fig. 10. Upper Chalk, near Brighton. British Museum, No. 5848. Left valve. 

 Natural size. 



I. Websteri, Mantell (Figs. 71, 72), has the posterior ear fairly well developed, 

 but not distinctly limited, and resembles I. Brongniarti of Mantell ; it is 

 characterised by the thinness of the shell and the sharp ridge-like folds, but forms 



