284 



CRETACEOUS LAMELLIBRANCHIA. 



sliire and West Norfolk ; ami 1)y Rowe from the zone of Holaster j;/«j(»s of Dover 

 and tlic Sussex coast, and from the zone of Mirraslev cor-tc.stndinnrium of Dover. 



Fiu. 39. 



Fk!. 40. 



Fig. 3"J. — hioceramus labiatus var latus, Sow. Zone of Hohister p/miiis, Swafl'ham, Norfolk. Nonvich 



Museum, No. 329(5. Eight valve and anterior view. Natural size. 



Fig. 40. — Inoceramvs labiatus var. Intvs. Sow. One of tlie types of Iiwceramvs latus, Sowerljy, 'Min. Conch.,' 



vol. vi, \i. I"i9, pi. ill.\.xxii, fig. 1 (lower figure). Swaffliam. British Museum, No. 43266. Natural size. 



Inoc'ER.uiiis i,.\ hiatus var. i,atus, SuirerJi;/, 1828. Text-figs. 38 — 40. 



1828. Inoceramus latus, /. du C. Soirerhij. Miu. Couch., vol. vi, p. 15ft, [,]. 



dlxxxii, fig. 1. (Noil /. hili/s, 

 Mantell). 



1854. — —J. Morris. Cat. Brit. Foss., ed. 2, p. 170 itnuilni)- 



TiriiKirls. — Tliis variety differs from /. luhinhi^ in the much greater length of 

 the hinge-line in proportion to the height of the shell, in the greater convexity of 

 the anterior margin, the smaller convexity of the ventral margin, and the less 

 oblique form of the shell. On account of the greater length of the hinge-line the 

 curvature of the ribs and growth-lines is broader than in /. luhidtns. 



This vai'iety appears to be confined to the zone of Ilolastev plaitit.'t, and is 

 common in the neighbourliood of Swaffham, Norfolk. The larger specimens which 

 I have seen are not sufficiently jierfect for figuring, but a characteristic exam^jle 

 is figured by Sowerliy. 



Types. — From the zone of IJoIa.^fer planus of Swaffliam. The smaller specimen 

 figured by Sowerl)y is in the British IMuseum (Fig. 40), but the larger specimen 

 cannot be found. 



Distrilmfion. — Zone of Ilolaster iilaniis of Purley Junction Station, Surrey, and 

 SwalTham, Norfolk. 



