35 



should never be disregarded. Some animals of seven- 

 teen years of age, and even in rare instances of 

 twenty-eight years old, will retain the marks in two 

 or more of the incisors ; nevertheless, as a general 

 rule, these signs are worthy of attention, and, taken 

 in conjunction with the illustrations presented in this 

 work, afford all that can be obtained to confirm the 

 judgment. 



17. Inhere are infundibula also in the molar teeth, 

 but not in all of them. Those of the lower jaw have no 

 infundibula, but only grooves or fissures, into which 

 the crusta petrosa dips, and which it fills up. The 

 manner of the arrangement will be seen in the table 

 of one of these teeth represented in figure 2, page 26. 

 In the same place, the wood -cut, figure 1, depicts the 

 grinding surface of one of the superior molars. Every 

 tooth of the last description, possesses two infundibula, 

 which extend almost to the root, and are possessed of 

 the same coverings as the like cavities in the incisors. 

 The crusta petrosa, however, which lines the infun- 

 dibula of the superior molars, is much thicker than 

 the similar membrane inverting the like parts in the 

 incisors; consequently, absolute cavities, answering 



D 2 



