H. Doc. 129. 33 



Mr. Blake has brought a finely preserved specimen of a medium 

 sized species of this genus from California. Rather smaller than 

 Ciircharodon angustidens, the tooth has the same form as that species, 

 only that there are no accessory points upon the sides of the hase. 

 Considering its size this tooth is remarkable for its thickness, and in 

 that respect it reminds one more of Garcharodon angustidens than any 

 other species. The surface is flat and the tooth straight, as in 

 C. anyustidens, and to this character the name rectus is intended to 

 allude. 



Several species of this genus have been described by Dr. R. W. 

 Gibbes as occurring in the tertiary of the Atlantic slope. 



OXYRHINA, Jlgassiz. 



7. o. PLANA, Agas. Since the teeth of Oxyrhina are known to 

 differ in size so widely as they do in the different parts of the jaws, 

 nothing is more difficult than ta combine fossil teeth found separated 

 in sucli a manner as to leave no doubt about their specific identity. 

 Several teeth of a very interesting species of Oxyrhina are found 

 among the specimens of fossils brought by Mr. Blake from California, 



and its resemblance to the 0. of the Mediterranean is very 



striking. But the character by which they differ most strikingly 

 from the living species and the fossils already described consist in the 

 greater flatness of the teeth as compared with their width. Some of 

 them are straight, and others slightly bent backward. This species I 

 propose to name 0. plo.na. 



Several species of this genus have been described from the 

 Atlantic States by Dr. R. W. Gibbes. 



8. o. TUMULA, Agas. The existence of a second species of the 

 genus Oxyrhina in the tertiary of California is indicated by several 

 teeth remarkable for the size and thickness of the roots as compared 

 with the lengths of their curves. The specimens agreeing in this 

 character differ greatly in size, and yet not more so than may be seen 

 in the same jaw of our living species. 



Found with the preceding by Mr. Blake. 



LAMNA. 



9. L. CLAVATA, Agas. Two teeth from Ocoya creek indicate the 

 existence in California of a species of Lamna allied to L. cuspidata of 

 the European Miocene, from which it differs, however, by its smaller 

 size, its shorter and narrower crown, in which respect it agrees more 

 with L. Hopei of Sheppy. The crown, however, is less arched than 

 the latter. The posterior surface is smooth as in L. cuspidata. 



Found with the preceding in the tertiary formation of Ocoya creek. 



10. L. ORXATA, Agass. A second species of Lamna has been brought 

 from California by Mr. Blake. It occurs in the sandstone of Navy 

 Point, Benicia, and is allied to L, elegans, Agass. (See Recherches 

 des Poissons Fossiles, vol. iii, p. 289.) It is, however, a smaller 

 species, and tapers more gradually, while in L. elegans it tapers more 



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