THE YEAR'S VERTEBRATE PALiEONTOLOGY 513 



form of Diprotodon. As regards general contour, Dr. Stirling 

 has followed the lines of a wombat, although with a certain 

 increase in the relative length of the limbs. Since, however, 

 the teeth and fore part of the skull are of the kangaroo type, 

 with some indications of a greater development of the soft 

 parts of the nasal region, the peculiar puffy and cushion-like 

 muzzle of the kangaroo has been introduced, in a somewhat 

 accentuated degree, into the restoration. 



Dr. Broom's recent work on the ancestry of mammals 

 receives mention at the end of the section on reptiles. 



Work on fossil birds during the period under review 

 appears, as usual, to have been but small. The discovery 

 of a leg-bone of a heron-like species in the Eocene of Egypt 

 has been already mentioned. Another lower Tertiary bird 

 has been identified by Dr. O. Abel {Cciitralblatt fur Miiicralogie, 

 1907, p. 450) in the shape of a large coracoid from the upper 

 Eocene of Choctaw Count}', Alabama, which had been mistaken 

 for a zeuglodont bone. That this bird, for which the name 

 Alabanioniis gigantca has been suggested, was of huge size, and 

 therefore flightless, is certain ; but whether it was related to 

 Diatryma of the North American and Gastoruis and Rcjuioniis 

 of the European Eocene must for the present remain doubtful. 



In connection with birds, reference may be made to an 

 exceedingly able and interesting paper on the origin of flight 

 in vertebrates by Baron Francis Nopcsa, published in the 

 June issue of the Proceedings of the Zoological Society of 

 London. In the opinion of the author, bats and pterodactyles 

 are the descendants of four-limbed arboreal creatures in which, 

 owing to the development of a fl3'ing-membrane (pafagiinn), the 

 fore-legs had become to a certain degree adapted for flight, and 

 in consequence less w^ell suited for terrestrial progression. 

 Birds, on the other hand, are regarded as having been evolved 

 from running bipedal dinosaur-like reptiles, in which the front 

 limbs, owing to a flapping movement, became modified into 

 wings, without any concomitant loss of the cursorial power 

 of the hind-limbs. It is on account of this superior mode of 

 development that birds have outstripped both pterodactyles 

 and bats in the contest for the " command of the air." They 

 may be likened to " aeroplanes," whereas their rivals have 

 not passed the "air-ship" stage. Baron Nopcsa's paper is 

 illustrated with a restoration of a cursorial " proavis." 



