THE TYPICAT, LEMURS. 23 



absence of certain subordinate features in some of the groups, 

 the family has been further subdivided into four sub-families. 

 The more important characters which they have in common are 

 the thick woolly fur, the Dog- or Fox-like snout and nostrils — 

 a character obviously distinguishing them from the bulk of the 

 Monkeys, in which the nose forms a subsidiary feature, and is 

 not the main part of the face, — and especially the number and 

 form of their teeth. In the centre of the upper jaw there is 

 always a toothless gap, or diastema^ on each side of which the 

 teeth are arranged according to the following formula : If, Cj-, 

 Pf, M| = 36. Among the Endrinas, however, the formula is 

 If, CysiTj-, Pf, M| = 32 or 30 in number. In the upper jaw the 

 incisors are small and perpendicular; but in the lower, where 

 they are long and narrow, they protrude horizontally in front, 

 and then follow, parallel and close to them, the somewhat 

 thicker canines, the six teeth together forming a comb-like 

 series. The anterior pre-molar is always vertically longer than 

 the others, and assumes the form and function of the canines 

 in other animals. 



In some genera (e.g., Propithecus), Milne-Edwards has ob- 

 served that in the young animal the cerebellum is more over- 

 lapped by the cerebrum (or main brain) than it is later in life ; 

 and Dr. Major believes that the Lemuridce are highly special- 

 ised members of the Sub-order, developed from ancient types 

 which were not unlike the American Monkeys of the family 

 Cchidce. 



The Typical Lemurs are arranged in the following four sub- 

 divisions : The Pottos and Slow-paced Lemurs {Lorisind); the 

 Galagos and Mouse-Lemurs {Galagince) ; the True Lemurs 

 (LemurincB) ; and the Endrinas ilndrisiiice) 



