27 



portion of the skull figured by Filhol in the Ann. Sci. 

 Geol. vol. vii. pi. xxix. fig. 143, showing the distinct 

 anterior talon and the low crown of pm. 2, and differing 

 thereby from No. M. 1351 (H. brachyrhynchus}. It appears 

 that the present specimen cannot, however, be distinguished 

 from the corresponding portion of the skull of H. aymardi 

 figured by Filhol in the Ann. Sci. Geol. vol. xii. pi. vii., 

 although that species is distinguished from H. leptorhynchus 

 by the presence of a distinct anterior talon to the last lower 

 premolar. Purchased, 1884. 



M. 1671. Fragment of the left ramus of the mandible, containing 

 the last premolar and the three true molars ; from the 

 Upper Eocene of Caylux. This specimen is precisely 

 similar to the corresponding portion of No. M. 1350. 



Purchased, 1884. 



M. 1672. Fragment of the right ramus of the mandible, containing 

 the last true molar ; from the Upper Eocene of Caylux. 

 The tooth has the elongated form characteristic of this 

 species and If, cayluxi ; in the relatively greater depth of 

 the jaw the present specimen agrees more nearly with 

 H. leptorhynchus than with H. cayluxi. (Vide Filhol, 

 Ann. Sci. Geol. vol. vii. art. 7, pp. 183, 206.) The 

 dimensions of the specimen are compared below with 

 those of the mandible of H. leptorhynchus described by 

 Filhol, viz. : 



Filhol. B.M. 



Length of carnassial 0,018 0,019 



Height of first lobe of carnassial . . 0,010 0,010 

 second 0,006 0,007 



Depth of jaw at carnassial 0,026 0,027 



Purchased, 1884. 



This species is about the size of H. brachyrhynchus; from which 

 it is at once distinguished by the much greater vertical depth of the 

 mandible. 



Hob. France. 



M. 1676. Fragment of the right ramus of the mandible, containing 

 the third and fourth true molars ; from the Upper Eocene 



1 Ann. Sci, GeoL vol. iii. art. 7, p. 29 (1872). 



