VERTEBRATE PALEONTOLOGY IN 191 1 567 



plumage in the extinct genus, the function and reduction of the 

 great toe (hallux) in birds and dinosaurs, the opposability of 

 the same toe in certain of the older groups of dinosaurs, the 

 homology and relative length of the bird's finger as compared 

 with its representative in the carnivorous dinosaurs, the function 

 of the claw in the living hoatzin {Opisthocomus) of South 

 America, the pose and mode of locomotion of the bipedal 

 dinosaurs, the functions of the hand and foot in the oldest 

 carnivorous members of that group, and the arboreal habits of 

 the ancestors of both carnivorous dinosaurs and birds, which it 

 is suggested may be known as " avidinosaurs." Archceopteryx, 

 it is pointed out, appears to have had a plumage resembling in 

 many respects that of the golden pheasant, and its flight was 

 almost certainly of the slow heavy type characteristic of many 

 game-birds. 



The prolonged and perhaps somewhat wearisome discussion 

 with regard to the normal pose of the limbs in Diplodocus and 

 other giant sauropod dinosaurs, to which considerable space 

 was accorded in my review for 1910, has been continued. In 

 the latter part of that year, for instance, Mr. F. Drevermann 

 (Sitz Ber. Ges. Naif. Freunde Berlin, 1910, pp. 399-401) criticised 

 the views of Dr. Tornier as to the squatting posture of these 

 reptiles, to which Dr. Tornier replied in the same issue 

 (pp. 402-5). The subject was resumed in the American 

 Naturalist for July, 191 1, by Dr. O. P. Hay, who once more 

 criticises the opinion that these reptiles carried themselves in 

 elephantine fashion, reasserting his own view that the general 

 pose was more after the crocodilian style. In regard to what 

 may be called the elephant-pose, it is pointed out that since a 

 straight femur appears to have characterised the proboscidean 

 (elephant) stock from the beginning, its occurrence in the 

 modern representatives of the group may be regarded as a 

 primitive feature, rather than an adaptation to the support of 

 great bodily weight. At the conclusion of his argument Mr. Hay 

 expresses doubts as to whether the erect bird-like posture attri- 

 buted to the carnivorous dinosaurs of the Jurassic is really true. 

 " The extraordinary development of the pubic bones of Aristo- 

 saurus, the expanded and anchylosed distal ends of which reached 

 nearly half-way to the fore-legs, seems to me to indicate that 

 these animals, when in repose, had a prone position, resting 

 much of the weight on the pubes, and that when running their 



