Davis — On the Fossil Fish of the Cretaceous Formations of Scandinavia. 371 



genus Otodus ; at the same time, regarding Otodus as a connecting link between 

 the two families, he considers that it is so close to the typical Lamnidse that it is 

 difficult to draw a line to divide them. 



Perhaps the most recent contribution to the subject is by A. Smith Woodward 

 in the Catalogue of the Fossil Fishes in the British Museum.* The great bulk of 

 the teeth of Lamna, previously described, are transferred to the genus Odontaspis, 

 and those of Otodus to the genus Lamna; Otodus, except as a synonym, 

 dropping out of the vocabulary. The Lebanon genus Rhinognathus renamed 

 Scaphanorhynchus is accepted, and included with it are some of the species of 

 Lamna (Odontaspis) described by Agassiz. Oxyrhina is retained without alteration, 

 and the teeth are defined as without denticles, but it is stated on another page that 

 some of the teeth of this genus have minute denticles. Woodward is of opinion 

 that " although only differing from Lamna in the prevailing absence of lateral 

 denticles in the teeth, it is convenient from a palseontological point of view to 

 retain Oxyrhina as a distinct genus, more especially as several forms of these 

 teeth bear specific names identical with those referable to Lamna proper." Lamna 

 acuminata, Agassiz f, is included as a synonym of Oxyrhina mantelli, Agass., 

 apparently on the authority of Sauvage, but that author % is doubtful whether the 

 teeth, figs. 55, 56, 57, are referable to L. acuminata, but has no doubt about fig. 

 54, which he accepts as the type of the species. If this view be correct, the tooth 

 represented by fig. 54, Woodward, to be consistent, should have included in his 

 genus Odontaspis ; the presence of well-formed lateral denticles clearly indicates 

 that genus. Carcharodon remains unchanged as a genus, but the species are re- 

 distributed. 



Sauvage § in the memoir abeady cited, points out that M. Reuss || has given a 

 figure of a tooth with feeble denticles, which that author considered to be an 

 example of Oxyrhina mantelli, Ag. Sauvage, however, gives reasons for believing 

 that the determination of Reuss is erroneous, and that the tooth ought be 

 classed with Otodus oxyrhinoides, Sauvage, It is probable that an equally 

 careful examination of other examples of teeth which possess evidence of lateral 

 denticles, would prove that they ought not to be considered as pertaining to 

 Oxyrhina, although they may have been found associated with undoubted teeth of 

 that genus, and described with them. 



Having thus briefly indicated the genera included in the family of the Lamnidae, 

 it is proposed to sum ujj the evidence, and if possible arrive at some reasonable 

 view for the classification of a group of fish-remains which are perhaps as per- 



* Part i., p. 349, et seq. 



f Poiss. Foss., vol. iii., p. 292, pi. xsxTii.ff, fig. 54 (? non figs. 55, 57). 

 X Poiss. Foss. de la Sarthe, p. 35. § Op. cit., p. 26. 



II Verst. der Bohm. Kreid., 1845, pi. iii., fig. 6. 



TKANS. EOT. DUB. SOC, N.S., VOL. IV., PAEI. VI. 3 H 



