256 
NATURAL HISTORY. 
consists of one incisor, no canine, one pre-molar, and three molars on both sides of the upper jaw • 
while below, the canine and pre-molar are entirely absent, the incisor and molar being like those of 
the upper jaw; it has thus eighteen teeth altogether. There are two front teeth in the upper 
and two in the lower jaw only, but they are very large, long, and narrow, being shaped like those 
of a Rabbit or Rat. Their tips wear away and expose a sharp cutting surface of thick enamel in front, 
and they are splendid cutting chisels. They gnaw and cut away wood, strip off bark, and make 
deep holes in the branches, and their length permits them to be placed in hollows in the wood so as to 
prize them open by acting as levers. It appears that they are made to grow from their sockets as they 
are worn down by frequent use. They are by themselves, and there is a great gap (diastema) or distance 
in the gums between them and the next teeth. This is quite after the fashion of the gnawing 
animals. The back teeth crush and champ fruit, vegetable substances, and insects with ease. 
There is a curious point about the chin, for there is no bony union there between the two sides of the 
lower jaw ; on the contrary, the union is by a more or less elastic tissue, which permits of some move- 
ment up and down and from side to side during the action of the great front teeth. * 
The hand is most peculiar, for certain of the fingers are so thin and long that they appear as if 
improperly nourished. They have the usual number of 
joints, and the last joints have strong curved claws. 
They have not the same relation of length and size as 
in any of the other Lemuroids, for the fourth finger is the 
longest instead of the third, and the third finger is so 
much more slim than the others, that Owen remarks that 
it seems as if it were paralysed. The hair is carried 
down the arms to the fingers, and adds to their spidery 
look. In the wrist there aro the usual nine bones, the 
intermedium being there in addition to the eight recog- 
nisable in the higher Apes; and the two bones of the 
fore-arm greatly resemble those of the Monkeys in 
general. 
The wrist and fore-arms are very movable, and the 
fingers also ; but the thumbs, small as they are, and 
clawed, have but little of the tliumb-like motion, and 
are but very slightly opposable to the forefinger, which, 
moreover, is rather shorter than the “ little ” or fifth 
finger. 
On the whole the Aye-Aye presents some re- 
semblance to the Lemuroids, and less to any other 
animal. Its large open ears, the eyes looking straight forward, the nostrils placed at the end of the 
snout, the want of any groove on the upper lip, the nature of the fur, so furry below and hairy above 
on the skin, are interesting to those who care to compare this animal with the Lemuroids and 
Rodents, or gnawing animals ; so are the perfect condition of the orbits, or eye cavities, in front and 
their opening through behind, and the arrangement of the back-bones and limbs to those who would 
compare it with the Monkeys. 
The skeleton resembles that of these last, and there are so many points of difference from the 
Rodents — although the skull at first sight looks like that of a Rat — that this very exceptional creature 
is classified with the Lemuroida from its partial resemblance to them and the Monkeys. 
THE CLASSIFICATION OF THE LEMUROIDA. 
Now that the Madagascar, African, and Asiatic Lemuroids have been noticed, and their promi- 
nent peculiarities described, it is easy to arrange them in the proper classification. Firstly, the 
# The formula of the milk set is— I. -f, C. M. f, = 12. That of the permanent set is— I. -f, C. -g, P. M. 
M. = 18. Professor Peters of Berlin moreover states his having found in a very early stage of development in the Aye- 
Aye, rudimentary teeth yielding a milk dentition — I. c. M. = 18. 
BONES OF THE HAND AND FOOT OF AYE-AYE. 
(After Owen.) 
