CHAT. XVII.] 



MAMMALIA. 



237 



Family 63.— CHINCHILLIE.E. (3 Genera, 6 Species) 



General Distkibution. 



The Chincliillida?, including the chinchillas and viscachas, are 

 confined to the alpine zones of the Andes, from the boundary of 

 Ecuador and Peru to the southern parts of Chili ; and over the 

 Pampas, to the Eio Negro on the south, and the River Uruguay 

 on the east. Chinchilla (2 sp.), the true chinchillas, are found 

 in the Andes of Chili and Peru, south of 9° S. lat., and from 

 8,000 to 12,000 feet elevation (Plate XXL vol. ii. p. 40) ; Lagi- 

 dmm (3 sp), the alpine viscachas, inhahit the loftiest plateaus 

 and mountains from 11,000 to 1G,000 feet, and extend furthest 

 nortli of ally of the family ; while Lagostmnus (1 sp.), the vis- 

 cacha of the Pampas, has the range above indicated. The family 

 is thus confined within the limits of* a single sub-region. 



Extinct Chinch ill idee. — Lagostomus has been found fossil in 

 the caves of Brazil, and in the l*liocene dej^osits of La 

 Plata. The only known extinct forms of this family are Aniblg- 

 7hiza and Loxomylus, found in cavern-deposits in the island of 

 Anguilla, of Post-Pliocene age. These are very interesting, as 

 showing the greater range of this family so recently ; though its 

 absence from North America and Europe indicates that it is a 

 peculiar development of the Neotropical region. 



Eamily 64— OCTODONTIDyE. (8 Genera, 19 Species.) 



General Distribution. 



Nf.gtropical 

 Sub-regions. 



1.2 



Nearctic 

 sub-kegions. 



Pal.«arctic 

 Sub-hegions. 



-2 



Ethiopian 

 Sub-regions. 



Oriental 



Sub- regions. 



AUSTRAMAir 



SuB-REGio:::. 



