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FOSSIL REPTILIA OF THE 



readers may know, assumes that God did not interpose to create one class of creatures 

 after another as the consequence of each geological revolution ; but that, through the 

 long course of ages, one class of creatures was developed from another. Now, Richard 

 Owen undertakes to demonstrate scientifically (and his demonstration is very rigorous) 

 that the arms and legs of the human race are the later and higher developments of the 

 ruder wings and fins of the vertebrated animals — that is, those which have a true back- 

 bone ; and he shows in the splint bones of the foot of a horse, bones analogous to those of 

 the fingers of the human hand. Therefore he concludes that God has not peopled the 

 globe by successive creations, but by the operation of general laws." 1 



The sole ground for Professor Flower's depreciatory remark is my acknowledgment 

 of being " as yet ignorant " 2 of the nature or way of operation of such general or secondary 

 laws; and I regret to say that after all that has been advanced since 1849 in the 

 endeavour to elucidate the way in which one species may be transmuted into another, I 

 am still in need of light. 



Assuming that the ornithic modification of the vertebrate archetype Avas one of those 

 under which the ' vertebrate idea ' became embodied in the course of progression from 

 " its old Ichthyic vestment," 3 two questions present themselves : — Out of what antecedent 

 vertebrate modification was the avian one evolved ? How, or under what conditions or 

 secondary influences, was such evolution effected? 



The hypothesis of the bipedal locomotion of the Dinosauria, the advocated homology 

 of their os pubis with the ischium of the bird, and the alleged restriction of the avian 

 antacetabular production of the iliac bone to the Dinosauria among Reptiles, have been 

 superadded to the proved fact of a correspondence of structure between the shorter 

 sacrum of the Dinosaurs and the longer sacrum of Birds as grounds for the conclusion 

 that Birds are transmuted Dinosaurs, and that the feathered class made their first step in 

 advance under the low form of Struthiones or Cursores, incapable, as yet, of flight. The 

 kind and amount of modification required to evolve an Ostrich out of an Iguanodon may 

 be appreciated by the osteological comparisons already submitted in the present mono- 

 graph. To revert only to the structure of the fore-limb. In losing its power of aiding 

 in the quadrupedal progression, and of grasping or otherwise applying the hand, it has 

 as yet, in the hypothetical first form of Birds, gained no other faculty. At best it may 

 help in the swift course of the ostrich by flapping motions similar to those of better birds 

 during their flight; or the more minute monodactyle hand may just serve to scratch the 

 back of the head, as in the New Zealand Kivi. In their larger extinct relatives, the 

 Moas, it is still doubtful whether more of the framework of a fore-limb existed than the 

 supporting scapular arch, and that of the simplest character. 



1 ' Little Lectures on Great Topics,' 12mo, 1849. 



2 ' On the Nature of Limbs,' p. 86. 



3 Ibid. 



