xviii INTRODUCTION. 



cene fauna. It has led nearly all to give a far higher value in classification to points of 

 difference than to those of agreement, and has left an indelible mark in the terminology 

 of the species — as, for example, in the Hymna spelcea of Goldfuss, and the Equus fossilis of 

 Professor Owen, which have not yet been proved to differ specifically from the living 

 spotted hyaena {H. crocuta) and the common horse {Equus caballus). The first law of the 

 distribution of fossils given by Professor Pictet is — " Les especes d'animaux d'une epoque 

 geologique n'ont vecu ni avant, ni apres cette epoque ; de sorte que chaque formation a ses 

 fossiles speciaux,et qu'aucune espece ne peut etre trouvee dans deux terrains d'age different" 

 — a law that is capable of disproof by the examination of any series of fossils stratigraphically 

 arranged. We find, on the contrary, that in proportion to the lapse of time between any 

 two formations, so the difference increases between their respective suites of organic re- 

 mains. If the interval between them be great, there may be no species and no genera in 

 common ; if it be small, a greater or less number of species or genera will be common to 

 both. In the case before us the interval between the Pleistocene times and our own is, 

 geologically speaking, small, and therefore we expect to find a large number of species and 

 genera in common. 



In the determination of these we purpose to give the maximum value to variations 

 within the limits of species that may be the result of difference of food, of climate, and 

 the like. But it may be objected that identity of osseous framework does not imply 

 identity of species where colour of the dermal covering is of weight — for example, that the 

 identity of form of the skeleton of Hycena spelcea with the H. crocuta does not imply that 

 the former Ayas spotted, or that close agreement between the Pleistocene and living Ursus 

 Arctos does not prove that the former was brown or black. To this we say that colour is 

 not, in our opinion, of specific value, changing even in the same individual according to 

 climate, as in the case of the Arctic wolves and many of the Arctic birds. The differences 

 in dermal covering, on the other hand, in all cases that have come before us, are correlated 

 also with differences in the skeleton, as in the recent lion and tiger. If the thick woolly 

 and hairy covering on the carcasses of the mammoth and tichorhine rhinoceros, imbedded 

 in frozen gravel on the shores of Siberia, be contrary to our experience of living species, 

 they were accompanied also by characters in the dentition and skeleton that prove the 

 species to which they severally belong to be extinct. Any argument, therefore, from them 

 to any other Pleistocene mammal, between which and the recent there is no difference in 

 hard parts, as the lion, falls to the ground. The value, indeed, of comparative osteology 

 depends upon the axiom, that identity of osseous framework and especially of that most ini' 

 portant part of the digestive apparatus, the teeth, implies also an identity of species. 



We have purposely omitted to burden this Introduction with references and notes, 

 which will be found in their proper place in the body of the work. 



himself disclaims these views of the Pleistocene fauna, and states, as his belief, " Je crois qu' entre le 

 moment ou les ossements des ours ont ete enfouis dans les cavernes et le temps actuel, il n'y a point en 

 de creation nouTelle, et point d'interruptioin dans la vie organique." — p. 360. 



