28 
UPPER MAMMAL GALLERY. 
in the same cage have attacked each other, the victor has eaten 
the whole of its opponent, leaving only the skin. A fast of 
three or four hours is fatal to most of them, so that the total 
number of worms and insects destroyed by the members of this 
order must be enormous. The range of the Insectivora extends 
over the whole world, with the exception of Australasia and 
South America. 
Fig. 16. 
Upper teetli of (A) the Tearec and (B) the Hedgehog. 
c, canines i, incisors ; molars ; p7n, premolars. 
Insectivora are not an easily defined group, since they 
contain many species in which certain parts of the skeleton 
are remarkably modified. Their teeth are strong and well 
developed, and, in the majority, clearly separable into the 
usual divisions ; but in some, such as the Shrews and Moles, 
the incisors, canines, and premolars are by no means readily 
distinguished from one another. Throughout the order the 
premolars and the molars are surmounted with minute pointed 
cusps, suitable for crushing the insects on which, as may be 
gathered from their name, nearly all Insectivora feed. The 
zygomatic, or cheek, arches are generally either weak or 
entirely absent. The dentition offers many important differ- 
ences, the Desmans [Myogale) having enormous incisors and 
