HYSTRICID^. 247 



the first and second true molars, the teeth in both speci- 

 mens being in an early stage of wear and in beautiful 

 preservation. The specimens are provisionally referred 

 by Waterhouse, in the passage quoted, to the present 

 genus, and are said to be too small to belong to Lund's 

 S. maf/nus ; the description of that form seems, however, 

 to be too vague to be certain on this point. The following 

 dimensions show the length of the space occupied by the 

 three true molars in the more perfect fossil and in two 

 specimens of the existing Erethizon dorsatus, viz. : 

 8. fossilis. E. dwsatus. 



0,0238 0,0208-0,0195. 



The superior size of these specimens probably indicates 

 at least their specific distinction from Erethizon dorsatus. 

 If they are identical with Synetheres magnus, that name 

 has the priority over S. fossilis. 



Claussen Collection. Purchased, 1845. 



Genus HYSTRIX, Linn. 1 



The teeth of this genus are indistinguishable from those of Athe- 

 rura ; but none of the living species of the latter attain anything 

 like the dimensions of the larger species of Hystrix. 



Hystrix refossa, F. Gervais 2 . 



Syn. Hystrix major, P. Gervais 3 (teste Schlosser). 

 Hob. Prance. 



34958-9. A right upper premolar and a first or second left upper 

 true molar 4 ; from the Upper Pliocene of Perrier (Puy- de- 

 Dome), France. The premolar appears to agree exactly 

 with the lower premolar figured by P. Gervais in the Zool. 

 et Pal. Frangaises, pi. xlviii. fig. 11, and both specimens 

 agree with the type in the complexity of the enamel-folds : 

 they appear rather larger than average specimens of H. 

 cristata, and thereby approach the Pleistocene so-called 

 H. major. Bravard Collection. Purchased, 1854. 



34957. Fragment of the base of the incisor, associated with the 

 above. Bravard Collection. Purchased, 1854. 



1 Syst. Nat. ed. 12, vol. i. p. 76 (1766). 



2 Zool. et Pal. Frangaises, 1st ed. vol. ii., explanation of pi. xlviii. (1848-52). 



3 Zool. et Pal. Generates, 1st ser. p. 76 (1876-79). 



4 Entered in the Itegister as Castor elaveris, Bravard, MS. 



