SPH^RA. 157 



Family— CORBID^), Ball 



Genus — Corbioella, ./. Morris and J. Lycett, 1853. 

 ('Moll. Great Ool.,' pt. ii, p. 94.) 



Corbicella claxbiensis, sp. now Plate XXIV, figs. 20 — 23. 



Description. — Shell oval, regularly convex, slightly inequilateral, anterior part 

 rather larger than the posterior part, length equal to nearly 1^ times the height. 

 Anterior margin rounded. Ventral margin convex, curving rapidly to join the pos- 

 terior margin which forms an angle with the nearly straight postero-dorsal margin. 

 Umbones broad, inconspicuous, scarcely curved, close together. Surface of shell 

 smooth except for growth-lines. 



Measurements : 



(1) (2) (3) (4) 



Length . 38 . 37 30 . 27 mm. 



Height . 26 . 25 . 21 . 19 „ 



(1 — 4) Claxhy Ironstone, Benniworth Haven. 



Remarks. — The genus Corbicella does not appear to have been recognised in 

 deposits of Cretaceous age, but since it is present in the Portlandian its occurrence 

 in the lower part of the Speeton Series of Lincolnshire causes no surprise. 



G. claxbiensis is similar in outline to some forms of G. Pellati, de Loriol, 1 from 

 the Portlandian. 



Type. — In the Sedgwick Museum, Cambridge. 



Distribution. — Spilsby Sandstone (zone of Belevrnites lateralis) of Claxby and 

 Donnington. Claxby Ironstone (zone of B. lateralis) of Benniworth Haven. 



Genus — Spilzera, J. Sowerby, 1822. 



('Min. Conch.,' vol. iv, p. 41.) 



Sph;era corrugata, Sowerby, 1822. Plate XXIV, fig. 24; Plate XXV, figs. 1, 2; 



text-fig. 26. 



1822. Sra^ERA corrugata, J. Sowerby. Min. Conch., vol. iv, p. 42, pi. cccxxxv. 

 1842. Venus cordiformis, A. Leymerie. Mem. Soc. geol. de Prance, ser. 2, vol. 



v, p. 5, pi. v, fig. 8. 



] De Loriol and Pellat, ' Jurass. de Boulogne-sur-mer ' (1875). p. 67, pi. xiv, fig. 12. 



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