190 ANIMAL LIFE PAST AND PRESENT. 



The skull of a dog conforms to the general structure 

 of the whole animal in its light and graceful shape, and 

 is characterised (among many other features) by the 

 presence of a bladder-like bone, covering the under 

 part of the internal ear, which is scientifically known 

 as the " bulla." The solid bony roof of the palate does 

 not extend farther back than the last tooth, and the 

 teeth are arranged in a gracefully curved line. There 

 are altogether eleven teeth on each side of the upper, 

 and twelve in the lower jaw ; the first three being called 

 the cutting-teeth, the fourth the eye-tooth, which is 

 readily distinguished by its tall crown, the next four 

 the false grinders, and the remainder (two in the upper 

 and three in the lower jaw) the true grinders. The 

 general arrangement of these is indeed precisely similar 

 to that which obtains in the Civet, a figure of the 

 upper teeth of which is given in Chapter XIV. (Fig. 64). 

 The most important features of these teeth are that the 

 last two in the upper jaw are triangular in shape (as is 

 shown in woodcut 57), the hinder being much smaller 

 than the preceding one, and that they are mainly 

 adapted for crushing, although they have an imperfect 

 cutting-edge on their outer side ; while the third tooth 

 from the hinder end of the jaw, which is termed the 

 " flesh-tooth," is longer than either of the other two, and 

 has a much higher crown, with a sharp cutting-edge, 

 which bites with a scissor-like action against the simi- 

 larly elongated and high-crowned "flesh-tooth" of the 

 lower jaw. This type of tooth structure indicates a crea- 

 ture whose diet consists mainly of animal subtances. 



