Notes

Abstract

To the large number of his palieontological discoveries Prof. Owen has quite recently added that of a most peculiar bird from the London clay of Sheppey, which he has named Odontotteryx toliapica. This new form, known only from the skull, though perfectly ornithic in general structure, and exhibiting many of the characters of the Steganopodes (Gannets and Cormorants), presents a peculiarity not found in any existing bird. The trenchant margins of the bones of both jaws, instead of being simple, are provided with long conical bony processes, like the serrations in a coarse saw. The posterior of these serrations, which are alone preserved, are directed somewhat forwards; the anterior were probably less inclined, or even directed backwards like the homologous horny processes in the Goosander. The theoretical importance of this new form is great; for it is as good an example as can be brought forward of the loss in modern times, from a persistent type of animals, of a well-developed specialised structure. Many who criticise the evolution hypothesis appear to assume that progress, or what is the same thing, development in the individual of a maximum number of specialised organs, is an indispensable element of the Darwinian hypothesis. Such, however, is certainly not the case after a certain degree of elaboration has been reached. For, taking Odontopteiyx as an example, it is evident that though this bird had in the struggle for existence acquired a dentigerous mouth, in which point it was in advance of all other members of the bird type, nevertheless its being thus able to obtain food which others could not hold, did not render it in the least less liable to be exterminated by many of the other accidents associated with existence. The upheaval of the sea-bottom, for instance, in its accustomed haunts, would have been destructive to it as to any other of its kind, and probably more so; for the specialisation of the jaws is certain to have been attended with a similar modification in the limbs, resulting in the loss of the power ot flight, which would not allow of its removing to a new locality on the change in the physical geography of its home. So with the equally modified Moa, Dodo and. Auk, the term of existence of the Odontopteryx was a short one, because the tendency of its development was too much towards a degree of uniformity in surrounding circumstances, which the human mind alone knows is not justified by facts.