rvORK IN PALAEONTOLOGY 145 



occurring in the Paris Basin, it was a most valuable, 

 ingenious, and yet obvious method, and even now is 

 the principal rule the palseontologist follows in identi- 

 fying fragments of fossils of any class. But it has its 

 limitations, and it goes without saying that the more 

 complete the fossil skeleton of a vertebrate, or the 

 remains of an arthropod, the more complete will be 

 our conception of the form of the extinct organism. 

 It may be misleading in the numerous cases of 

 convergence and of generalized forms which now 

 abound in our palseontological collections. We can 

 well understand how guarded one must be in working 

 out the restorations of dinosaurs and fossil birds, of the 

 Permian and Triassic theromorphs, and the Tertiary 

 creodonts as compared with existing carnivora. 

 As the late O. C. Marsh * observed : 



" We know to-day that unknown extinct animals 

 cannot be restored from a single tooth or claw unless 

 they are very similar to forms already known. Had 



discouraging the Blumenbachs and Soemmerings from giving their 

 attention to this kind of work." 



Huxley has, inter alia, put the case in a somewhat similar way, to 

 show that the law should at least be applied with much caution to 

 unknown forms : 



" Cuvier, in the Discours stir les Revolutions de la Surface du Globe, 

 strangely credits himself, and has ever since been credited by others, 

 with the invention of a new method of paleontological research. But 

 if you will turn to the Recherches sur les Ossemens fossiles, and watch 

 Cuvier not speculating, but working, you will find that his method is 

 neither more nor less than that of Steno. If he was able to make his 

 famous prophecy from the jaw which lay upon the surface of a block 

 of stone to the pelvis which lay hidden in it, it was not because either 

 he or any one else knew, or knows, why a certain form of jaw is, as 

 a rule, constantly accompanied by the presence of marsupial bones, 

 but simply because experience has shown that these two structures are; 

 coordinated " (Science and Hebrew Tradition. Rise and Progress 

 of Paleontology 1881, p. 23). 



* History and Methods of Paleontological Discovery (1879). 



