Davis — On the Fossil Fish of the Cretaceous Formations of Scandinavia. 413 



between Corax pristodontus and Corax falcatus. They have a vpell-marked indenta- 

 tion, or notch, on the posterior margin, and at the same time exhibit a long, 

 arched extension of the anterior margin over the root, and the base of the crown 

 on the external surface is rounded. They may either be considered as a connect- 

 ing link uniting the two species, or as an independent species. 



M. Reuss (" Verst. der. Bohmischen Kreideform," 1845, pt. i., p. 3) has 

 expressed the opinion that only one species of Corax existed during the Cretaceous 

 era, to which he gave the name 0, heterodon, including in it C. kaupii, C. falcatus, 

 C. appendiculatus, and C. affinis, of Agassiz. M. Herbert (" Mdmoii-es de la Soc. 

 Gfeol. de France," 1854, ser. ii., vol. v., p. 353) arrived at a similar conclusion after 

 a very careful study of a large number of specimens from the Chalk of Meudon 

 and Cotentin, embracing all the variations between Corax kaupii and C. pristo- 

 dontuSj and he suggested the name Corax pristodontus, Ag., as being the earliest, 

 under which all the others should be affiliated ; whilst M. Pictet was led to 

 remark (Pictet et Campiche, "Foss. Crdtacd de Sainte Croix," 1858, ser. ii., p. 80) 

 that there was very small probability that so many and varied forms could be 

 associated on the jaws of the same fish ; and M. Sauvage says that it is not to 

 be supposed that only a single species had lived in the Cretaceous seas from the 

 epoch of the Grault to that of the Maestri cht beds (" Biblioth de I'Ecole des Hautes 

 fitudes," 1872, vol. v., art. 9, p. 40). 



In the midst of so many learned opinions, a clear and definite judgment on this 

 difficult and intricate set of phenomena is impossible. There may be some hope 

 that a complete dental series may be found which will exhibit the natural 

 arrangement; but until this happens all classification must of necessity be 

 provisional. Whilst recognizing the possibility that many of the specimens 

 now supposed to represent separate species may ultimately be proved to have 

 been associated in the same jaws, it may be advantageous to consider them 

 as distinct until material shall be acquired which will render their determination 

 certain. 



Formation and Locality. — Etage S^nonien Superieur : Kopinge ; Etage S^nonien 

 Inferieur (zone with Actinocamax mammillatus, Nills.) : Ifo ; Oretorp ; Ignaberga ; 

 Oppmanna; Balsberg, 



Ex coll. — Riksmuseum, Stockholm ; Geological Museum of the University of 

 Lund. 



3N 2 



