ON THE TEETH OF MAMMALIA, 135 



Hog (Sua Babirussa), the canine teeth in the upper jaw are curved upwards'so 

 as to form a semicircle, and often a complete circle. In the common Wild Boar 

 the tusks are often of immense size, and very powerful weapons of offence and 

 defence. In the Bear there are two small canine teeth between the large ones 

 and the molars, and which are also separated from these latter by a considerable 

 interval. Canine teeth are found in the Solidungula (Horse) under the appella- 

 tion of tushes, which are also some distance from the molar teeth. Some have 

 even affirmed that this space was left purposely to receive the bit. The Seals 

 also possess canine teeth, and all their molars partake considerably of the same 

 nature, beinw pointed and sharp. In the Ruminanlia we find the camel supplied 

 with these teeth. The Musk (Moschus -.noschiferus) has a long canine tooth on 

 each side of the upper jaw, projecting in the male considerably beyond the lips. 

 The Bat family is provided with four large canine teeth. These teeth in the 

 Mole have two roots like false molars. 



III. Molares, Back, Molar, or Grinding Teeth. — These teeth are found in all 

 Mammalia that have any teeth ; their form is very various, and adapted to the 

 food and manners of the animal. Thus we see the crown of the molar teeth in 

 Carnivorous animals sharp and angular. In the Graminivorous animals, on the 

 contrary, the crowns are broad and flat, and more or less grooved, as their food 

 requires to be much bruised preparatory to digestion. In Omnivorous animals 

 (as Man) these teeth are elevated and more or less angular at the edges, and 

 depressed in the centre. In all classes they are fully adequate to perform the 

 part allotted to them in the function of digestion. The Armadilloes, and the 

 Cape Ant-eater, have molars, but are destitute of incisores or canine teeth. 

 The Narwhale is the only exception to the rule laid down above, as it has merely 

 its tusks, which are inserted into the intermaxillary bone, and are therefore 

 incisors. In Man and the Quadrumana or Monkies, the two front molars are 

 smaller in the crowns, and more simple in the roots than the more posterior ones. 

 In these as well as the Camivora (Lion, Tiger, Dog, &c), and some Rodenlia (as 

 the Marmot) the crown is covered with enamel. In the Horse, Sheep, Cow, 

 Elephant, &c, bony substance is seen on the upper surface of the tooth, running 

 in lines of different forms in each order. In all these animals the enamel runs 

 down into the body of th« tooth to a considerable depth. In Graminivorous 

 animals that do not ruminate (as the Horse, Elephant, &c.) the crowns of the 

 molar teeth lie nearly in an horizontal direction with respect to each other. In 

 most of the Ruminants the surface of these teeth is oblique, the outer margin of 

 the upper, and the inner one of the lower tooth being most prominent. In the 

 Camivora (as the Dog, Lion) the crowns of the molar teeth are uneven, and end 

 in pointed processes with depressions between them ; these lock into the cor- 



