CHAPTER XII. 
The Insectivores,— Order Insectivora. 
The absence of any vernacular name for that group of Mammals, of which the 
shrews, moles, and hedgehogs are the best known representatives, compels us to 
adopt an anglicised form of the Latin term by which the group is known; 
and we accordingly use the term Insectivores in this sense. This term, it is almost 
superfluous to add, refers to the insect-eating habits of most of the members of 
this order, and it is a good one, since, with the exception of the bats, there is no 
other group of Mammals which prey so exclusively on insects, or other small 
creatures. 
Most of the Insectivores are comparatively small-sized animals; and, with the 
exception of the family of tree-shrews, and some of the aquatic forms, all are of 
more or less purely nocturnal habits. In the absence of any very strongly-marked 
characteristics, like the wings of the bats, the group is by no means easy of strict 
definition,—more especially when we have to avoid entering into the consideration 
of abstruse anatomical details. 
In addition to their generally small size and nocturnal habits, the 
Characteristics '' ^ 
Insectivores may immediately be recognised by the following struc¬ 
tural features. All their toes are furnished with claws, and are in most cases five 
in number on each foot; while in no instance is either the thumb or the great toe 
capable of being opposed to the other digits. They walk either on the whole, or 
the greater portion, of the soles of their feet; and never on their toes only, in the 
manner of a cat or dog. Their upper molar teeth carry a number of small and 
sharp cusps, which are arranged either in a Y-shaped or a W-shaped pattern; and 
their incisor teeth, of which there are not less than two pairs in the lower jaw, 
never assume the chisel-like form found in all the Rodents (rats, porcupines, 
hares, etc.); but the first or innermost pair is very frequently larger than either 
of the others, thereby distinguishing them from the Carnivores. In no instance 
is one pair of the cheek-teeth in each jaw ever modified so as to act with 
the scissor-like action characteristic of so many of the Carnivores. Then 
again the tusks, or canine teeth, are generally not markedly distinct from the 
other teeth, 1 so that it is frequently a matter of some difficulty—especially in the 
lower jaw—to decide which teeth are incisors, which tusks, and which premolars. 
This may be readily verified by comparing the skull of a hedgehog with that of 
a dog, in which the tusks cannot possibly be confused either with the incisors in 
front, or with the premolars behind. 
If, ao-ain we examine the skeleton of an Insectivore, it will be found that 
? to * 
there are (with the exception of an African and a Malagasy species) always a pair 
i This is not so in the common tenrec, which has large tusks. 
