200 
LEMURS. 
thumb and great toe; but, curiously enough, in some of them the index finger of 
the hand is rudimentary. They may or may not have tails, but these are never 
prehensile, although, as in some of the marmosets, they may be marked by alternate 
dark and light rings. 
A point of resemblance to the monkeys and apes is shown by the number of 
incisor, or front teeth, being very frequently two on each side of both jaws, in 
place of the three which are so commonly present in other Mammals. In the 
apes and monkeys, however, the central pair of incisors in the upper jaw are in 
SKELETON OF SQUIRREL-MONKEY ( 1 ), OF MONGOOSE LEMUR ( 2 ), AND OF SLENDER LORIS ( 3 ). 
contact with one another, while in the lemurs they are almost invariably separated 
by a gap in the middle line. This affords a ready means of distinguishing the skull 
of a lemur at a single glance from the skulls of almost all other Mammals except 
bats and some of the Insectivores. The lower front, or incisor, teeth of the 
lemurs shelve forwards, after the manner we have already mentioned as character¬ 
istic of one group of the American monkeys (p. 173). 
Many lemurs are purely nocturnal animals, and it was probably from this cir¬ 
cumstance, coupled with their silent habits and stealthy movements, that Linnaeus 
was induced to give them the name by which they are now universally known. 
It is, perhaps, almost superfluous to mention that the name lemur is taken from 
the Latin term lemures, which, together with that of larvae, was applied by the 
