THE DOG. 



91 



FIG. 49. 



while those of the dorsal vertebrsB incline from front to 

 back. In man and in the monkeys that maintain an 

 erect posture all the spinal processes incline from front 

 to back. 



The skull of a dog presents no striking feature, but the 

 face is very different from that of man. The branches 

 of the lower maxillary bone are proportionally much 

 elongated, and are almost straight, while the articu- 

 lating condyle is transversely developed in the form of 

 a roller, permitting only an up-and-down motion of the 

 jaws, and no lateral movement as in man. 



The powerful jaws of the dog constitute his only 

 weapon and his only means of defence. The mouth is 

 slit far back, permitting it to open very wide ; the motor 

 muscles of the jaws 

 are very strong; they 

 are so attached to the 

 bones as to afford the 

 quickest and the 

 strongest action. 



The dog is construct- 

 ed for rapid running, 

 and has only rudiment- 

 ary clavicles ; his paws 

 and feet are formed by 

 the same bones as in 

 man, and their position 

 is more or less vertical. 

 There are five digits to the forefeet, the thumb being 

 recognizable by its shortness. The hindfeet have only 

 four digits. When the dog stands, his metacarpal bones 

 do not touch the ground ; they are in an almost vertical 

 position, and the foot rests on the phalanges. Even the 



B Incisors 

 A Canines 



A Canines 



B Incisors 



Molars 



JAWS AND TEETH OF DOG. The skin has 

 been cut away in order to show the 

 teeth. 



