Zoological Society, ^^ 



to point out their adaptation to support an expanded membrane. 



[l/'iZ 



but not pinions *." 



The reply to this assertion need only be a simple reference to jji^ 

 ture : sections of the wing-bones of birds may be seen in the Museuin 

 of the Royal College of Surgeons, and have been exposed to view, 

 since the discovery of their structure by the Founder of that Collec- 

 tion, in every Museum of Comparative Anatomy worthy to be so 

 called. 



To expose the gratuitous character of the objection above cited, I 

 have placed on the table a section of the very bone that directly sus- 

 tains the large quill-feathers in the Pelican ; its parietes are only half 

 as thin as those of the antibrachial bone of the great Pterodactyle 

 which is figured in my * History of British Fossil Reptiles,' pi. 4, and 

 is not thicker than those of the bone figured in the Geological Trans- 

 actions, 1840, above cited. 



Hunter, who had obtained some of the long bones with thin 

 walls and a wide cavity from the Stonesfield slate, has entered them 

 in his MS. Catalogue of Fossils as the "Bones of Birds," and per- 

 haps no practical anatomist had had greater experience in the degree 

 of tenuity presented by the compact walls of the large air-cavities of 

 the bones in that class. Of all the modifications of the dermal system 

 for combining extent of surface with lightness of material, the ex- 

 panded feather has been generally deemed the consummation. Well 

 might the eloquent Paley exclaim, ** Every feather is a mechanical 

 wonder : their disposition all inclined backwards, the down about the 

 stem, the overlapping of their tips, their different configuration in dif- 

 ferent parts, not to mention the variety of their colours, constitute a 

 vestment for the body so beautiful and so appropriate to the life 

 which the animal is to lead, as that, I think, we should have had 

 no conception of anything equally perfect, if we had never seen it, or 

 can imagine anything more so." It was reserved for the author of 

 the * Wonders of Geology ' to prefer the leathern wing of the Bat and 

 Pterodactyle as the lighter form, and to discover that such a structure 

 as is displayed in the bone described and figured in the ' Geol. Trans.* 

 vol. vi. pi. 39, was a most improbable one to have sustained a power- 

 ful wing of any bird ! f Let me not be supposed, however, to be 

 concerned in excusing my own mistake ; I am only reducing the 

 unamiable exaggeration of it. Above all things, in our attempt to 

 gain a prospect of an unknown world by the difficult ascent of the 

 fragmentary ruins of a former temple of life, we ought to note the 

 successful efforts, as well as the occasional deviations from the right 

 track, with an equal glance, and record them with a strict regard to 

 truth. The existence of a species of Albatros, or of any other actual 

 genus of bird during the period of the Middle Chalk, would be truly 

 a wonder of Geology ; not so the existence of a bird of the longipen- 

 nate family. 



I still think it for the interest of science^ in the present limited 

 ext^t of induction from microscopic observation, .to offer a warning 



. * Mantell, ' Wonders of Geology,' 1848, vol. i. p, 44^. ^]\ii^,^.Ji^^^ .' j„j^ 



