THE DENTITION OF THE DOG. 419 



outer incisor is larger than the others, and its middle 

 cusp is very large, while the outer is rudimentary. The 

 large canine has a strong, curved, pointed crown, with a 

 longitudinal ridge along its posterior face. The crowns of 

 the anterior three premolars are triangular, with a smooth- 

 cutting anterior edge ; the hinder edge is also shai-p, but is 

 divided by a notch into two lobes, of which the hinder 

 is the smaller. These teeth are two-fanged. The fourth 

 premolar is a large tooth. In form, its crown has a general 

 similarity to that of the foregoing; but, firstly, the pos- 

 terior lobe is relatively much larger, and pointed, so as 

 to form an obvious second cusp; and, secondly, a strong 

 process of the crown projects inwards from its anterior 

 end, and is supported by a distinct fang — so that this pre- 

 molar is three-fanged. It is termed a carnassial, or sec- 

 tonal, tooth, as it bites like a scissor-blade against a cor- 

 responding tooth in the mandible. The preceding teeth 

 have cutting crowns; but those of the molars are broad and 

 crushing. They exhibit an outer division, formed by two 

 large subequal cusps, and an inner division, also presenting 

 two cusps, the posterior of which is much smaller than 

 the anterior. In addition, the cingulum sends tip a strong 

 process on the inner side of the crown. 



In the lower jaw, the crowns of the incisors, the outer of 

 which is the largest, are all trilobed. The outer cusp is 

 stronger than the inner in all, and particularly in the outer, 

 incisors. The canines resemble those of the upper jaw. 

 Each premolar has two fangs and a sharp triangular crown, 

 the posterior edge of which is trilobed, as in the upper 

 premolars ; but the posterior lobe is small in the fourth, 

 which differs but little from the rest. The first molar, on 

 the other hand, is a large tooth, with a blade-like crown, 

 which bites against the inner side of the upper fourth pre- 

 molar, and is called the carnassial or sectorial tooth of the 

 lower jaw. The crown is elongated, and presents a large 

 anterior external cusp, divided into two lobes by a deep 

 notch. On the inner side of this is a small internal 

 cusp. The two posterior cusps are very much lower than 



