THE TRUE LEMURS. 67 



have one main cusp to the outside ; the anterior pre-molar, 

 however, has a supplementary minute front cusp, while the 

 median has in addition one large interior cusp ; both it and 

 the posterior pre-molars are vertically taller than their anterior 

 fellow. The molars have two inner cusps, and two main outer 

 cusps with a supplementary minute fore cusp, as well as two 

 cusps on the ridge joining the fore and hind outer cusps ; the 

 posterior molar — the smallest of the three — is, however, larger 

 than the posterior pre-molar, and has only the front inner cusp 

 and no supplementary external cusp. The lower jaw shows a 

 gap between the canine and the anterior pre-molar. The 

 anterior pre-molar, which is vertically taller than the rest, is 

 edged and cutting, taking the place of a tusk ; the anterior and 

 median pre-molars are also separated by a small space; the 

 latter, which is equal in vertical height to the posterior, has an 

 inner cusp and a low cusped heel. The molars have two outer 

 main cusps, of which the front one is more developed than the 

 hind one, and two inner cusps, often with an intermediate cusp 

 between them ; the pair of fore and the pair of hind cusps are 

 joined by transverse ridges, and the two outside cusps by a 

 backwardly directed semicircular ridge ; the posterior molar is 

 four-cusped. 



The dorsal and lumbar vertebrae together do not exceed 

 twenty in number. 



The hind portion of the cerebellum is large, which points to 

 intellectual inferiority in the True Lemurs as compared with 

 the Apes. 



The species of this genus are all confined to the island of 

 Madagascar and some of the smaller adjacent islands. They 

 are gregarious, living in large companies in the forests, feeding 

 on fruits, insects, and such small animals, birds, and lizards 



F 2 



