3 12 
INSECT! VO RES. 
bats, which appear to be the ancestral groups of the order to which they belong, 
having in all probability been directly derived from insect-eating Insectivores. 
The cobego should, indeed, be regarded rather as the sole representative of a side 
branch, which, while to some extent simulating the bats, never gave rise to any 
descendants showing the special modifications for true flight. 
The Tree-Shrews, or Tupaias. 
Characteristics. 
Family TuPAUDsE. 
With the tree-shrews, or tupaias, we come to the first family of the true 
Insectivores, or those which are incapable of flight, and have their front or incisor 
teeth of a normal form. 
The tree-shrews, which are entirely confined to the Oriental region, take their 
name from their strictly arboreal habits; and are small, long-tailed animals, so 
closely resembling the smaller squirrels in external appearance as to be frequently 
mistaken for them. Indeed, it appears that the native term Tupai, from which 
these animals derive their second title, is applied indifferently by the Malays both 
to them and to squirrels; the affix Tana serving to denote the members of the 
present group. That they have really nothing to do with the squirrels is shown 
by an examination of their teeth, when it will be found that, instead of the 
single pair of chisel-like incisor teeth, they have two pairs of small incisors in 
the upper jaw, and three pairs in the lower. 
The tree-shrews belong to a group of Insectivores characterised 
by their upper molar teeth having broad crowns carrying a number 
of cusps arranged in the form of the letter W. They are peculiar in that the 
socket of the eye, or orbit, is surrounded by a bony ring, whereas in other members 
of the order it is open behind. They are further distinguished from the other true 
Insectivores not only by their completely arboreal, but likewise by their diurnal, 
habits, as they feed entirely by day. They resemble squirrels in the general 
form of the body and limbs, and in possessing a more or less bushy tail. 
They have 38 teeth, of which | are incisors, canines, and § cheek-teeth, on 
either side of each jaw. Their feet, like those of squirrels, are naked beneath, 
with moderately curved and sharp claws. The muzzle is sharply pointed, the ears 
are small and rounded, and the long hair of the bushy tail is confined to its upper 
surface and sides, the under-surface having much shorter hair. 
Altogether, there are about a score of species of the genus 
Tupaia, which have a wide distribution over the Oriental region. 
They are found in India, Burma, the Malay Peninsula, the Nicobar Islands, 
Sumatra, Java, Borneo, and the Philippines. They are very much alike in general 
appearance, the species differing mainly in respect of size and colour, as well as 
in the length of the fur. Many are restricted to particular islands; the Bornean 
tree-shrew, the Nicobar tree-shrew, and the recently discovered Philippine tree- 
shrew, being unknown out of the islands from which they take their names. 
Others, again, have even a still more restricted distribution; two species having 
hitherto been obtained only in the forests of Mount Dulit in North Borneo. 
