348 PALAEONTOLOGY. 



only infer it to be more probable that the fossil was a Herbi- 

 vore than an Insectivore or a mixed-feeding Carnivore. 



Admitting the herbivority of the fossil, it is not certain 

 that it was hoofed ; there is nothing in the form and structure 

 of the tooth to prove ■ that. Both form and structure are 

 compatible with the hoofless muticate type of herbivorous 

 Mammal, as shewn by the Manatee ; it is the small size of 

 the Stereognathus which renders it less probable that it was a 

 diminutive kind of Manatee, and more probable that it was a 

 diminutive form of Ungulate. But seeing the manifold 

 diversities of the multi-cuspid form of molar teeth in recent 

 and extinct insectivorous unguiculate quadrupeds, it is not 

 impossible but that the Stereognathus may have belonged to 

 that order ; there is no known physiological law forbidding it. 



The form of the cusps, and their regular symmetrical 

 arrangement in the Stereognathus, as compared with the known 

 modifications of multi-cuspid molars in certain small extinct 

 forms of hoofed quadrupeds, constitute the sole ground upon 

 which an opinion is formed of its most probably belonging to 

 the same section of Ungulata, But nothing is known of the 

 comparative anatomy of the family of quadrupeds to which 

 the Stereognathus belonged. Its peculiar type of grinding 

 tooth may have been combined with modifications of the 

 skeleton so far different from those of any now known, as to 

 have constituted a peculiar marsupial family with a type of 

 skeleton as distinct as that which Cuvier inductively studied 

 in the feline Carnivores (fig. 160), and in the ruminant Herbi- 

 vora (fig. 161), whereby he was enabled to enunciate that 

 beautiful law of the " correlation of forms and structures," the 

 application of which will be subsequently illustrated. 



In the ratio of the knowledge of the reason of the coinci- 

 dences of animal structures — in other words, as those coinci- 

 dences become "correlations" — is our faith in the soundness 

 of the conclusions deduced from the application of such law. 



