CLASSIFICATION. 355 



with considerable confidence, but he has also pointed out 

 that such inferences are likely from time to time to prove 

 mistaken. I will quote his own words : 



* If a fragmentary fossil be discovered, consisting of no 

 more than a ramus of a mandible, and that part of the 

 skull with which it articulated, a knowledge of this law 

 may enable the palaeontologist to affirm, with great con- 

 fidence, that the animal of which it formed a part 

 suckled its young, and had non-nucleated red blood-cor- 

 puscles ; and to predict that should the back part of that 

 skull be discovered, it will exhibit two occipital condyles 

 and a well-ossified basi-occipital bone. 



' Deductions of this kind, such as that made by Cuvier 

 in the famous case of the fossil opossum of Montmartre, 

 have often been verified, and are well calculated to im- 

 press the vulgar imagination ; so that they have taken 

 rank as the triumphs of the anatomist. But it should 

 carefully be borne in mind, that, like all merely empirical 

 laws, which rest upon a comparatively narrow observa- 

 tional basis, the reasoning from them may at any time 

 break down. If Cuvier, for example, had had to do with a 

 fossil Thylacinus instead of a fossil Opossum, he would 

 not have found the marsupial bones, though the inflected 

 angle of the jaw would have been obvious enough. And 

 so, though, practically, any one who met with a character- 

 istically mammalian jaw would be justified in expecting 

 to find the characteristically mammalian occiput associ- 

 ated with it ; yet, he would be a bold man indeed, who 

 should strictly assert the belief which is implied in this 

 expectation, viz., that at no period of the world's history 

 did animals exist which combined a mammalian occiput 

 with a reptilian jaw, or vice versa! 



One of the most distinct and remarkable instances of 

 correlation in the animal world is that which occurs in 

 ruminating animals, and which could not be better stated 



A a 2 



