STEREOGNATHUS. 34<7 



with a more complete conversion of the food into chyle and 

 blood, — and that such more efficient type of the whole diges- 

 tive machinery should be correlated, and necessarily so, with 

 the hot blood, quick-beating heart and quick-breathing lungs, 

 with the higher instincts, and more vigorous and varied acts 

 of a Mammal, as contrasted with a cold-blooded reptile or 

 fish, — is also conceivable. To the extent to which such and 

 the like reasoning may be true, or in the direction of the 

 secret cause of the constant relations of many-rooted teeth 

 discovered by observation, — to that extent will such rela- 

 tions ascend from the empirical to the rational category of 

 laws. 



The interest which the above-described fossil from the 

 Stonesfield oolitic slate excites is not exclusively due to its 

 antiquity, its uniqueness, or its peculiarity ; much is attached 

 to its relations as a test in palaeontology of the actual value of 

 a single tooth in the determination of other parts of the 

 organization of the animal. According to our opinion of these 

 unseen parts, we frame our expression of the nature and 

 affinities, or of the place in the zoological system, of the 

 extinct species. From the resemblance of the lower molars 

 of Stereognathus to those of Pliolophus, which, though not 

 close, is closer than to the teeth of any other known animal, 

 it is probable that the Stereognathus was hoofed, and conse- 

 quently herbivorous, or deriving the chief part of its subsis- 

 tence from the vegetable kingdom. Cuvier has written, — 

 " La premiere chose a faire clans l'etude d'un animal fossile est 

 de reconnaitre la forme de ses dents molaires ; on determine 

 .par la s'il est carnivore ou herbivore, et dans ce dernier cas, 

 on peut s'assurer, jusqu'a un certain point de l'orclre d'herbi- 

 vores auqnel il appartient."* In the case in question the 

 form of the molar teeth of one jaw is recognizable, but the 

 herbivority of the fossil is not thereby determined. We can 



* Osseraens Fossiles, 4to, torn, iii., 1822, p. 1. 



