and of the Determination of Fossils. 293 



which it belonged could use its feet only for walking, and 

 that, consequently, it has been herbivorous, and of the divi- 

 sion Ungulata. We may thence conclude, that it had teeth 

 fitted for bruising plants ; no clavicule ; large ribs ; and, in 

 its whole skeleton, more strength than suppleness. These 

 rational methods, the varied and important applications of 

 which this example will enable us to understand, furnish the 

 first data for classifying and recomposing the animal ; but 

 they cannot lead us beyond certain generalities. Thus a 

 bone, which proved to a certainty that an animal was herbi- 

 vorous, will be often of no use in affording more detailed in- 

 formation ; and we shall be unable, by confining ourselves to 

 the rigorous application of the theoretical principle, to infer 

 from it, for example, whether it was a ruminant, whether it 

 had horns, and whether these horns were solid or hollow. 

 The use of the rational means^ then, is commonly insufficient 

 for the determination of the genus ; their office is limited 

 to tracing out the great features of the organism of the 

 fossil animal, without the power of adding thereto the ne- 

 cessary details. 



But the principle of the concordance of characters also fur- 

 nishes us with empirical means, which perform an important 

 part when the rational means desert us. The animals which 

 form natural genera not only resemble each other in the cha- 

 racters which are necessary to secure for them the same 

 kind of life ; they are likewise similar, in the greater part of 

 the details of form, which, at first glance, might appear alto- 

 gether secondary, and useless to study. Each bone, consi- 

 dered relatively to the whole of a natural genus, usually pre- 

 sents a uniform physiognomy, which results from the ana- 

 logy of the forms of the details in the majority of the spe- 

 cies ; the apophyses, the crests, the cavities, the articular 

 surfaces, have a close resemblance to each other in all the 

 species. If, on the contrary, we compare the same bone with 

 its analogues in the allied genera, we shall notice pretty de- 

 cided differences in these same accessory characters; and 

 this comparison of analogies in the same genus, and of dif- 

 ferences with the allied genera, will afford the foundation for 

 the empirical means of determination which we now speak 



