380 Zoological Society, 



fitted for any special adjustment to aerial locomotion j and in the pre- 

 sent day we know of no species of the class that can sustain itself in 

 the air which equals a Sparrow in size. And the species in question — 

 the little Draco volans — sails rather than flies, upborne by its out- 

 stretched costal parachute in its oblique leaps from bough to bough. 



Of the remarkable reptiles now extinct, which, like the Bats, had 

 their anterior members modified for plying a broad membranous wing, 

 no species had been discovered prior to 1840 which surpassed the 

 largest of the Pteropi, or Flying-Foxes, in the spread of those wings, 

 and there was, h priori, a physiological improbability that the cold- 

 blooded organization of a Reptile should by any secondary modifica- 

 tion be made to eifect more in the way of flight, or be able to raise a 

 larger mass into the air, than could be done by the warm-blooded 

 Mammal under an analogous special adaptation. When, therefore, 

 the supposed bird's bone (Geol. Trans. 1840, pi. 39. fig. 1) was first 

 submitted to me by Dr. Buckland, which on the Pterodactyle hypo- 

 thesis could not be the humerus, but must have been one of th^ 

 smaller bones of the wing, its size seem.ed decisive against its reference 

 to an animal of flight having a cold-blooded organization. The sub- 

 sequent discovery of the portion of the skull of the Pterodactyle, de- 

 scribed by Mr. Bowerbank at the last meeting of the Society (Jan. 

 14), shows that the resources of Creative power in past time surpass 

 the calculations that are founded upon actual nature. 



It is only the practised Comparative Anatomist that can fully realize 

 the difficulty of the attempt to resolve a palseontological problem from 

 such data as the two fragments of long bones first submitted to me in 

 1840. He alone can adequately appreciate the amount of research 

 involved in such a generalization as that " there is no bird now known, 

 north of the equator, with which the fossils can be compared ;'* and 

 when, after a wearying progress through an extensive class, the spe- 

 cies is at length found to which the nearest resemblance is made by 

 the fragmentary fossil, and the difl'erences are conscientiously pointed 

 out — as when, in reference to the humerus of the Albatros, I stated 

 that " it differs therefrom in the more marked angles which bound 

 the three sides** — the genuine worker and searcher after truth may 

 conceive the feelings with which I .find myself misrepresented as 

 having regarded the specimens " as belonging to an extinct species 

 of Albatros.'* My reference of the bones even to the longipennate 

 tribe of natatorial birds is stated hypothetically and with due caution : 

 " On the supposition that this fragment of bone is the shaft of the 

 humerus, its length and comparative straightness would prove it to 

 have belonged to one of the longipennate natatorial birds equalling in 

 size the Albatros." (loc. cit. p. 41 1 .) ''^^ 



Since the discovery has been made of the manifestly characteristid 

 parts of the genus Pterodactylus in the Burham chalk-pit, it has been 

 objected that the bones first discovered there, and described by me 

 as resembling birds of flight, *' are so extremely thin, as to render it 

 most improbable that they could ever have sustained such an instru- 

 ment of flight as the powerful wing of the Albatros, or of any other 

 bird : their tenuity is in fact such," says the ex post facto Objector, 



