ir,o CRETACEOUS LAMELLIBRANCHIA. 



Genus— MUTIELLA, Stoliczha, 1871. 



(' Palaeont. Indiea, Cret. Fauna S. India,' p. 247.) 



Mutiella ? canaliculata (Sowerby), 1836. Plate XXV, figs. 4 — 6. 



1836. Peteicola canaliculata, J. de G. Sowerby. Trans. G^ol. Soc, ser. 2, vol. 



iv, pp. 241, 341, pi. xvi, 

 fig. 11. 

 nucifoemis, Sowerby. Ibid., pp. 241, 341, pi. xvi, fig. 10. 

 1850. Caedium canaliculatum, A. d'Orbigny. Prodr. de Pal., vol. ii, p. 163. 



nucifoeme, d'Orbigny. Ibid., p. 163. 

 1854. Peteicola? canaliculata, J. Morris. Cat. Brit. Foss., ed. 2, p. 220. 



— nucifoemis, Morris. Ibid., p. 220. 



1866. Caedium canaliculatum, F. J. Pictet and O. Campiche. Foss. Terr. Cret. 



Ste. Croix (Mater. Pal. 

 Suisse, ser. 4), p. 270. 

 1865-66. Peteicola nucifoemis, Pictet and Campiche. Ibid., pp. 163, 276. 

 1870. canaliculata (Caedium), F. Stoliczka. Palaeont. Indica, 



Cret. Fauna S. India, vol. 

 iii, p. 141. 

 nucifoemis (? Coebis), Stoliczka. Ibid., p. 141. 



Description. — Shell inflated, outline more or less orbicular, inequilateral, length 

 and height equal. Margins rounded. Anterior margin less convex than the pos- 

 terior margin. The latter makes an obtuse angle with postero-dorsal margin and 

 curves rapidly to join the ventral margin. The margin in front of the umbo 

 expands. Umbones large, contiguous, curving inward and forward. No lunule. 



Ornamentation consists of numerous, regular, radial ribs, separated by narrow 

 furrows, and crossed by narrow concentric ridges which are more prominent 

 on the posterior part of the shell than elsewhere. Inner margins of the valves 

 crenulate. 



There are two cardinal teeth in the left valve and one in the right. Behind 

 the umbo a long, nearly straight, sharp ridge forms the inner margin of the 

 ligament groove. 



(2) (3) (4) 



. 19 . 17 . 14-5 . 10 mm. 



11) . 17 . 14-5 . 10 „ 

 (1—4) Blackdown. 

 Affinities. — The generic position of this species has been for a long time a 

 matter of doubt, but no one appears to have accepted Sowerby 's view. The 



isurements ; 







(i) 



Length 



20-5 



Height 



20-5 



