282 ■ MAMMALS. 



I am not aware that fossil remains of any species of this family have been discovered. 



Jerboas. (DiPODiDiE.) (Map 82.) In Johnston's " Physical Atlas," the range of the Jerboa is laid 

 down as limited to an irregular ellipse of no great size, occupying the space between the Caspian Sea 

 and Egyjjt. Its range is vastly more extensive than this. In fact, it is spread almost over the 

 whole world, with the exception of South America, the Indian region, and Australia ; and over Aus- 

 tralia, too, if we reckon Hapalotis as belonging to the group. It stretches, on the one hand, across 

 MongoKa and Siberia to Amourland, and, on the other hand, across the Sahara to the Atlantic. 

 Nor is this aU : the genus Jaculus of North America belongs to the same family, and it extends 

 o-ver the whole of that continent, from the Atlantic to the Pacific. The family is composed of four 

 genera, and fourteen or fifteen species. One of the genera, Pedetes, with a somewhat Kangaroo- 

 like external appearance, is peculiar to the Cape of Good Hope. 



