Prof.S. G. Seeley — On Vogt's Vieio of the Archmopteryx. 307 



as the ancestors of the whole bird class. And, without undervaluing 

 the avian similitudes of Dinosaurs, the author believes that " all the 

 characters whereon are based the claim of Dinosaurs to be regarded 

 as the ancestors of Birds are only related to the power of keeping 

 an upright position upon the hind feet." This is too large a subject 

 to enter into now, for it involves the whole question of how far per- 

 sistent function, when identical in character, may develope in allied 

 groups of animals nearly identical structures. Vogt believes that 

 certain Dinosaurs were leaping or perching animals, and infers that 

 the avian characters of the pelvis and hind-limb thus came to be 

 evolved from community of habit with birds. He is, however, not 

 indisposed to see in Dinosaurs possible parents of the Eatites ; while 

 the ArclicBopteryx would be the ancestor of the Birds that fly. The 

 bird class, however, seems to me remarkably homogeneous in vital 

 structures, and also in such characteristics of the skeleton as are 

 common to the class. 



In this view Struthious birds, far from being a degenerate group 

 which had lost their wings, would be a primitive group which 

 had not reached active flight. But the RatitcB have far too much 

 in common with carinate birds to permit a suspicion that they have 

 originated in a fundamentally diiferent way from a different stock. 

 The Dinosaurs are far too diverse to permit a suspicion that they 

 are the direct ancestors of any Birds. The dinosaurian armour is 

 about the last thing in the world that would suggest feathers, and it 

 is difficult to conceive of any advantage in the struggle for existence 

 which would lead to Dinosaurs becoming feathered, if the feather 

 were not developed into an organ of flight. It is true that many 

 Dinosaurs may have been naked, but that does not justify us in pre- 

 suming that the skin contained the germ plan of the ostrich feather, 

 which time would inevitably develope. Still less is there anything 

 in Dinosaurian structure to suggest that the saddle-shaped inter- 

 vertebral articulation of the centrum in a Struthious bird would 

 spring into existence side by side with the same structure in the 

 vertebral column of a carinate bird, if the latter had been derived 

 from a fundamentally different stock. 



While Vogt thus regards the two existing groups of birds as having 

 ancestral representatives in the Jurassic rocks, no evidence is detected 

 of a common ancestor. It is, perhaps, remarkable that in this dis- 

 cussion the Pterodactyles are omitted from comparison with the 

 ArclicBopteryx. There are, however, some points remarked upon in 

 the earlier portion of the memoir which may be here noticed. This 

 skeleton is said to show no trace of a pneumatic structure, thus 

 differing from Pterodactyles. I cannot quite agree with Prof. Vogt 

 when he affirms that Pterosaurs were never able to hold themselves 

 upright as do birds, because their hind-feet were very weak, short, 

 and furnished with slender digits. It might be well to study the 

 skeleton of the original Pterodactylus longirostris figured by Cuvier 

 and many others, or, if this were too small, the Dimorphodon macronyx 

 from the Lias would show an animal well capable of walking in the 

 position of a bird, while the Gycnorhamphus suevicus, at Tiibiugen, 



