HISTORY OF THE PRIMATES 579 



tion, instead of being directed forward, as they are in the An- 

 thropoidea ; they are encircled in bone, but are not walled in 

 by a bony funnel ; the lachrymal bone is extended on the face 

 and the foramen is outside of the orbit. The hind legs are 

 longer than the fore ; the humerus retains the epicondylar 

 foramen and the femur has a third trochanter ; the feet are 

 plantigrade, almost always five-toed, with opposable thumb 

 and great toe, and having a varying proportion of flat nails 

 and sharp claws. The brain is of a primitive type and not 

 much convoluted. 



All the existing and most of the fossil lemurs are small 

 animals, some quite minute, and only in the Pleistocene of 

 Madagascar have large ones been found. They are chiefly 

 nocturnal and arboreal in habits, and feed upon fruit and leaves, 

 but vary their diet with insects, small reptiles, birds and eggs. 

 Their present geographical distribution is very remarkable ; 

 more than two-thirds of the existing species are confined to 

 Madagascar ; the others are in tropical Africa, southern Asia 

 and the Asiatic islands, as far east as Celebes and the Phihppines. 

 In the Eocene epoch they extended all over the northern hemi- 

 sphere, but have not been found in any subsequent formation 

 outside of their present range. 



Lemurs occurred in the Uinta stage, but were much more 

 abundant in the Bridger, of which the best-known genus is 

 ]Notharctus. These Eocene forms did not have the aberrant 

 peculiarities of the modern lemurs, but departed less from the 

 primitive stock common to both of the suborders. In ]Noth- 

 arctusihQ dental formula was : ff, c {, p |, m |, X 2 = 40, the den- 

 tition being reduced only to the extent of losing one incisor on 

 each side above and below ; the lower canine was not incisiform 

 nor had the anterior premolar taken its place ; the upper molars 

 were quadritubercular, and in the lower ones the anterior 

 triangle was hardly higher than the heel. The two halves of 

 the lower jaw were coossified at the symphysis, and the femur 

 had lost the third trochanter. It is not likely that ^Notharctus 



