INOCERAMUS. 335 



1854. Inoceramus cordiformis, J. Morris. Cat. Brit, loss., ed. 2, p. 169. 

 1°97. .R. Leonhard. Palaeontographica, vol. xliv, |». 48. 



1898 - Haenleini, G. Mailer. Mollusk. Untersen. v. Braunschweig 



u. Ilsede (Abhandl. d. k. preuss. 

 geol. Landesanst., n.f., 25), p. 41, 

 pi. v, fi£. 7; pi. vi, figs. 1, 2. 

 ? 1911. cordiformis, W. Rocjala. Bull. Iiitemat. Acad. Sci. Ciacovie, 



p. 170, pi. iv, fig. 2. 



Non 1904. C. Airaghi. Boll. Soc. geol. Italiana, vol. xxiii, 



p. 189, pi. iv, figs. 6—9. 



Description. — Shell inflated, equivalve, very inequilateral, rounded. Anterior 

 margin more or less nearly straight or undulating, but rounded in large specimens. 

 Ventral and posterior margins more or less sinuous. Anterior part of valves 

 more or less flattened and often nearly perpendicular to the plane between the 

 valves. Postero-dorsal part of valves much compressed and usually wing-like. 

 Hinge equal to more than half the height of the shell. Umbones terminal, large, 

 prominent, curved inwards and forwards. A broad, shallow sulcus extends from 

 behind the umbo to the postero-ventral extremity and separates two broad, 

 rounded ridges. A similar sulcus may extend from the front of the umbo to the 

 opposite ventral margin. 



Ornamentation consists of broad, rounded, concentric folds, which bend 

 upwards where they cross the two radial sulci. The folds become less distinct 

 on the anterior and postero-dorsal parts than on the sides of the shell. Numerous 

 close-set growth-lines are present. 



Affinities. — I. Haenleini, Miiller, 1 from the lower part of the Lower Senonian of 

 Brunswick and Ilsede, seems to be hardly distinct from /. cordiformis. The 

 smaller English specimens agree very closely with one of the examples figured by 

 Miiller (pi. v, fig. 7). 



I. cordiformis resembles some of the more convex forms of I. Lamarcki, 

 Parkinson, from which it is distinguished by the equal size of the valves and the 

 presence of radial sulci. The specimen, figured (PI. LIV, fig. 1), connects this 

 species with I. Lamarcki. 



Remarks. — Goldfuss' fig. 66 is a copy of Sowerby's figure ; his fig. 6a is the 

 type of /. saxonicus, Petrascheck. 



Type. — In the British Museum, No. 43277, from the Upper Chalk (zone of 

 Micraster cor-anguinum) of Gravesend (PI. LIII, fig. 8). 



Distribution. — Zone of Micraster cor-testudinarium of Clanfield (Hampshire), 

 and Wharram Percy (Yorkshire). Zone of Micraster cor-anguinum of Gravesend, 

 Micheldever, and Porton. Uintacrinus band of Salisbury. Senonian of Haldon. 



1 'Mollusk. Untersen. v. Braunschweig u. Ilsede' (1898), p. 41, pi. v, fig. 7; pi. vi, figs. 1, 2. 



