BIRD OR REPTILE WHICH? 7 z 7 



Prof. Marsh thinks that probably it possessed bi-concave segments in 

 its backbone, indicating, therefore, some alliance with the ichthyornis. 

 The structure of its wings, Prof. Huxley points out, differs in some 

 very remarkable respects from that which they present in a true bird. 

 In the archaeopteryx the upper arm-bone is like that of a bird, and the 

 two bones of the forearm are more or less like those of a bird ; but 

 the fingers, which in all modern avian representatives are fused 

 together into one mass, are not bound together they are free. What 

 the number may have been is uncertain, but several, if not all, of them 

 were terminated by a strong-curved claw ; so that in the archaeopteryx 

 we have an animal which to a certain extent occupies a midway place 

 between a bird and a reptile. It is a bird in so far as its foot and sun- 

 dry other parts of its skeleton are concerned; it is essentially and 

 thoroughly a bird by its feathers : but it is much more properly a rep- 

 tile in the fact that the region which represents the hand has separate 

 bones with claws resembling those which terminate the fore-limb of a 

 reptile. Teeth and a long tail, moreover, have certainly been considered 

 hitherto non-avian characteristics. 



More recently in our own country there has been brought to light 

 from the London clay, in the island of Sheppey, a skull with the mar- 

 gins of the jawbones armed with larger alternating with smaller den- 

 ticulations. It has been submitted to the examination of Prof. Owen, 

 facile princeps among the restorers of osteological remains, who con- 

 cludes that it belonged "to a warm-blooded feathered biped with 

 wings " to a bird, in fact " and further, that it was web-footed and 

 a fish-eater, and that in the catching of its slippery prey it was assisted 

 by the peculiar armature of its jaws." Many living birds, such as the 

 mergansers or saw-bills, have denticulatiocs on the borders of the 

 horny covering of the bill ; but no modern bird has ever the underly- 

 ing bone elevated into ridges or denticulations like those seen in the 

 London-clay fossil. On the palate, however, of the rare Phytotome, a 

 South American perching bird belonging to the group of the Leafcut- 

 ters, which bears in its structure many " marks of ancientness," we 

 find two rows of bony denticulations, the remains of what are appar- 

 ently but recently lost teeth, if we calculate time by the geological 

 horologe, and which may be faint memorials of the dental arrangement 

 seen in the chameleon. Certainly, " they are not the less of interest, 

 seeing that as yet we have nothing else intervening between them and 

 the teeth of the Sheppey fossil." How far this fossil may have resem- 

 bled any of the avian remains which we have described above, we 

 must wait to know. To conjecture would be dangerous, considering 

 how wide of the mark would have been, in all likelihood, the restora- 

 tion, had any been attempted, of the hesperornis, whose true structure 

 when revealed so greatly surprised the most experienced naturalists. 

 All that can at present be said is, that the owner of the solitary skull 

 could not have claimed a place within the old avian province. It is 



