202 Mammals of Eastern Asia 
likeness to one another, at least externally. They are found 
through most of the area being considered in this book except 
the Malay Peninsula. 
Of the several Oriental genera of the Hare family that have 
been distinguished, most may be set aside as not occurring in 
our area. Among those that can be so neglected are the True 
Rabbits, Oryctolagns, of Europe and northern Africa (the 
American "Rabbits" are species of Hares), the peculiar Sumat- 
ran Hare, Nesolagiis, and the Luchu Island Hare, Pentalagus. 
The young of the True Rabbits are born in a relatively undevel- 
oped condition, with little or no hair, whereas those of all others, 
so far as known, are born with a good coat of hair. 
Only two genera of Hares need be considered. These are the 
True Hares, genus Lepus, and the Harsh- furred Hare, genus 
Caprolagus. Lepus and Caprolagus are separated by characters 
of the skull and teeth that can best be appreciated when the 
skulls are compared. External characters of Caprolagus include 
relatively coarse fur, extraordinarily short ears (for Hares), 
short tail and feet, and generally reddish brown coloring. The 
Indian and Burmese groups of Lepus may also be somewhat red- 
dish and have coarse fur, but although their feet are as short 
as in Caprolagus their ears are considerably longer. 
All the Hares, whether Caprolagus or Lepus, have a groove 
down the front of each of the large upper incisor teeth. In the 
Lepus timidus group and the L. europmis group this groove is 
shallow and uncomplicated; but in a third group comprising 
most of the Hares of the Indian and Burmese lowlands, the 
groove is enlarged and deepened and its internal walls are fluted 
and channeled in a direction parallel with the main groove. The 
entire groove may be concealed by a filling of comparatively soft 
cement, just as is the case with the folds in the teeth of the 
horses and elephants. In America some of the Hares of Texas 
and Mexico also exhibit this folded tooth structure. Examples 
of the Hares that possess such deeply grooved teeth are the 
Black-naped Hare, L. nigricollis, of the Indian Peninsula; the 
