Fish-remains from the Parana Formation. 5 



1896. Carcharias (Aprionodon) Gibbesii, G. de Alessandri, loo. eit. 



p. 721, pi. i. fig. 3. 

 1896. Corax aff. falcatus, G. de Alessandri, loc. cit. p. 722, pi. i. fig. 4. 



The meaning of Bravard's specific names quoted above is 

 indicated by his labels in the British Museum and in the 

 National Museum, Buenos Aires. Two teeth in the British 

 Museum marked Lamna obliquidens are upper lateral teeth 

 of Carcharias (Prionodon) ; numerous specimens in the 

 National Museum labelled Lamna serridens are obviously 

 upper teeth of the same species, while other specimens labelled 

 Lamna amplibasidens in both museums are for the most part, 

 if not all, lower teeth of the same fish. The majority of the 

 lower teeth are distinctly serrated, like the specimen erro- 

 neously referred to C. {Aprionodon) Gibbesi by Alessandri ; 

 but many of the smaller specimens exhibit quite smooth 

 edges — possibly a character of immaturity *. Some of the 

 upper teeth have been referred to Corax by Alessandri ; but 

 I have made sections of several examples identical in shapa 

 with that represented in his fig. 4, and found all to have 

 a central cavity. I therefore regard his determination of 

 Corax from the Parana formation as a mistake. 



9. Galeocerdo aduncus, Agassiz. (PI. I. figs. 10, 10 a.) 



1835-43. Oaleocerdo aduncus, L. Agassiz, op. cit. vol. iii. p. 231, 



pi. xxvi. figs. 24-28. 

 1889. Galeocerdo aduncus, A. S. Woodward, Catal. Foss. Fishes B. M. 



pt. i. p. 444. 



Like those of Carcharias the species of Oaleocerdo are 

 difficult to determine, but the tooth from Parana represented 

 in PI. I. figs. 10, 10 a, seems to belong to the side of the 

 jaw of the European and North-American Miocene species 

 O. aduncus. It is readily distinguished from the Eocene 

 G. latidens by its deeper crown and finer serrations. 



10. Hemipristis serra, Agassiz. (PI. I. figs. 11, 11a.) 



1835-43. Hemipristis serra, L. Agassiz, op. cit. vol. iii. p. 237, pi. xxvii. 



figs. 18-30. 

 1889. Hemipristis serra, A. S. Woodward, Catal. Foss. Fishes B. M. 



pt. i. p. 449. 



This species is rare in the Parana formation, but a few 

 well-preserved upper teeth are unmistakable. The best 

 specimen, not in the least abraded, is shown in PI. I. 

 figs. 11, 11a. It is in all respects a typical upper tooth. 



* A. Gunther, Catal. Fishes B. M. vol. viii. (1870) p. 357. 



