THE TYPICAL 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 das/ema, on each side of which the 
teeth are arranged according to the following formula: I%, C4, 
P23, M3=36. Among the Endrinas, however, the formula is 
12, Cray, P2, 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 Zemurid@ are highly special- 
ised members of the Sub-order, developed from ancient types 
which were not unlike the American Monkeys of the family 
Cebide. 
The Typical Lemurs are arranged in the following four sub- 
divisions: The Pottos and Slow-paced Lemurs (Zorisine); the 
Galagos and Mouse-Lemurs (Galagine); the True Lemurs 
(Lemuring) ; and the Endrinas (Zudrisine) 
