HYSTEICIB^;. CHZNCHILLID.E. 249 



specimen is not adult. The first tooth in each jaw is the 

 prernolar, and the second the first true molar. On the left 

 side of the mandible the whole length of the crown of m71 



Fig. 33. 



Hystrix sivalensis (?). Left lateral aspect of the cranium of a young individual, 

 with the nasals restored ; from the Siwalik Hills. \. (From the ' Palaeon- 

 tologia Indica.') 



is exposed ; and it is thus seen that in its lower part the 

 dimensions of this tooth are similar to those of the corre- 

 sponding tooth of the type mandible represented in fig. 32. 

 Presented by Generals Sir W. E. Baker, K.C.B., 

 and Sir H. M. Durand, K.C.B., 1848. 



Family CHINCHILLID^l. 

 Dentition:!. \, C. ?, Pm. -}, M. |. 



Gtenus LAGOSTOMUS, Brookes 1 . 

 Hagogtomud trtdjottactylus, Brookes 2 . 

 Hob. S. America. 



M. 1339. The cranium, mandible, and greater portion of the skeleton; 

 from the Pleistocene of Buenos Ayres. Purchased, 1882. 



43246. Part of the cranium and mandible ; from the Pleistocene of 

 Buenos Ayres. Presented by Senor L. J. Fontana, 1871. 



1 Trans. Linn. Soc. vol. xvi. p. 102 (1828). 2 Loc. tit. 



