COMPARATIVE ANATOMY OF THE TEETH. 



287 



canine 1, bicuspids 4, molars 3, The number of milk 

 teetli is made twenty-eight. Incisors 3, canine 1, molars 

 3, to both jaws on either side, 



In the Peccari the dental formula numbers thirty-eight 

 teeth i. e. in the upper jaw, on each side, there are, inci- 

 sors two, canine one, bicuspids three, molars three; in the 

 lower, on each side, are, incisors three, canine one, bicus- 

 pids three, molars three. 



The Horse, (equidce) This noble and useful animal, be- 

 longing to the family solidungula, or singlQ-hoofed variety, 

 has forty teeth. In both jaws, on each p IGi 79> 

 side, there are three incisors, one canine, 

 three bicuspids, and three molars. 



The lower canines, according to M. Cu~ 

 vier, are only sometimes present in the 

 male, and always wanting in the female. 

 Between the canines and first bicuspids 

 there is a wide space corresponding to the 

 angle of the mouth, where the bit is re- 

 ceived. The incisors are slightly curved, 

 having long, subtrahedral fangs, taper- 

 ing to their extremity, and closely ar- 

 ranged in the segment of a circle. These 

 teeth, says Mr. Owen, are distinguished 

 from those of all other animals "by the 

 fold of enamel which penetrates the body 

 of the crown from its broad, flat summit, like the inverted 

 finger of a glove." This fold encloses a cavity, which pre- 

 sents the form of an island, when the tooth begins to be 

 worn. This cavity is partly filled by "cement, and partly 

 by the discolored substances of the food, and is called the 

 mark." It is described as being usually obliterated, in the 

 middle incisors, about the sixth year in the second inci- 

 sors, about the seventh; and the third, about the eighth, 



FIQ. 79, A longitudinal section of the Incisor of a Horse, e Enamel. 

 d Dentine, c Cement. c Cement reflected into the depression of the 

 crown, s Colored tartar and food filling up this cavity and constituting what 

 is known as the " mark" and made use of to tell the age of the horse. 



