DENTAL SYSTEM 29 
trenchant, and piercing, and are situated wide apart, so as to give 
the firmest hold when fixed in the victim’s body. The jaws are as 
short as is consistent with the free action of the canines, so that no 
power may be lost. The incisors are very small, so as not to 
interfere with the penetrating action of the canines, and the 
crowns of the molar series are reduced to scissor-like blades, with 
which to pare off the soft tissues from the large bones, or to divide 
into small pieces the less dense portions of the bones for the sake of 
nutriment afforded by the blood and marrow they contain. The 
gradual modification between this and the two following types will 
be noticed in their appropriate places. 
In the most typical insectivorous animals, as the Hedgehogs 
and Shrews, the central incisors are elongated, pointed, and project 
forwards, those of the upper and lower jaw meeting like the blades 
of a pair of forceps, so as readily to secure small active prey, quick 
to elude capture, but powerless to resist when once seized. The 
crowns of the molars are covered with numerous sharp edges and 
points, which, working against each other, rapidly cut up the hard- 
cased insects into little pieces fit for swallowing and digestion. 
The omnivorous type, especially that adapted for the con- 
sumption of soft vegetable substances, such as fruits of various 
kinds, may be exemplified in the dentition of Man, of most 
Monkeys, and of the less modified Pigs. The incisors are moderate, 
subequal, and cutting. If the canines are enlarged, it is usually 
for other purposes than those connected with food, and only in the 
male sex. The molars have their crowns broad, flattened, and 
elevated into rounded tubercles. The name Bunodont, or hillock- 
toothed, has been proposed for molars of this type, and will 
frequently be found convenient. 
In the most typically herbivorous forms of dentition, as seen in the 
Horse and Kangaroo, the incisors are well developed, trenchant, and 
- adapted for cutting off the herbage on which the animals feed ; the 
canines are rudimentary or suppressed ; the molars are large, with 
broad crowns, which in the simplest forms have strong transverse 
ridges, but may become variously complicated in the higher degrees 
of modification which this type of tooth assumes. 
Various forms of teeth of this type will be noticed among the 
Ungulates and Rodents. 
The natural groups of mammals, or those which in our present 
state of knowledge we have reason to believe are truly related to 
each other, may each contain examples of more than one of these 
modifications. Thus the Primates have both omnivorous and 
insectivorous forms. The Carnivora show piscivorous, carnivorous, 
insectivorous, and omnivorous modifications of their common type 
of dentition. The Ungulata and the Rodentia have among them 
the omnivorous and various modifications, both simple and complex, 
