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Theories of the Origin of Birds. By 

 William K. Gregory. Annals of the 

 New York Academy of Sciences, Vol. 

 XXVII, pp. 31-38. New York. Pub- 

 lished by the Academy, May 4, 1916. 



In this paper, Dr. Gregory, starting 

 with the demonstrated fact that birds arc 

 of reptilian origin, has summarized, from 

 the point of view of comparative anatomy, 

 palaeontological knowledge and inference 

 concerning the ancestors of Arclucoplcryx, 

 'the oldest known fossil bird, of the Jurassic 

 period.' He favors the hypothesis that 

 birds were evolved from 'Pseudosuchian' 

 reptiles of the Permian and Trias, from 

 which also came the specialized dinosaurs, 

 pterosaurs, etc. (reference to the work of 

 Dr. Robert Broon). The highly special- 

 ized avian hind limbs and bipedal loco- 

 motion were acquired by terrestrial or 

 arboreal forms before the complete spe- 

 cialization of the fore limbs for flight 

 (reference to the work of Prof. H. F. 

 Osborn and Baron Francis Nopcsa). 

 Feathers, from specialized scales (reference 

 to the work of Mr. W. P. Pycraft), and the 

 power of flight arose in very active rep- 

 tilian animals. High stable blood-heat, 

 correlated with this activity, was con- 

 served by feathers. Development of the 

 feathers of the wing to brace against the 

 air augmented the considerable activity of 

 the already bird-like reptile and launched 

 it on its initial flight as the 'first bird.' 



A recent interesting paper by Mr. C. W. 

 Beebe is spoken of, according to which 'in 

 the young of various species of doves, 

 pigeons, jacanas and owls there is a 

 reduced pelvic wing,' and Dr. Gregory 

 disposes of the hypothesis of a dual origin 

 for birds as 'in the writer's judgment, en- 

 tirely untenable.' 



Dr. Gregory has taken up the problem 

 of the evolution of the bird in connection 

 with a Columbia University course on 

 vertebrate development, and his paper will 

 be especially useful to the general student 

 because of its concisensess, conservatism 

 and forcefulness. It gives a sound basis 



for investigation on avian ancestry. Many 

 of the facts presented are not new. Prob- 

 ably they have never been so carefully 

 balanced nor so successfully interpreted. 

 One of the chief bones of contention is 

 whether flight first evolved among bipedal, 

 leaping, terrestrial animals or among par- 

 achuting, arboreal ones. Kx|K)nents of 

 both theories arc (juotcd at length, and the 

 author, while himself favoring the hypoth- 

 esis of arboreal ancestry, is not convinced 

 that the ancestors of birds 'held the arms 

 perfectly still throughout the gliding leap.' 

 His bridge of hypothesis from reptile to 

 bird inspires confidence, and should hold 

 well until intermediate fossils are un- 

 earthed to render it no longer necessary.— 

 J. T. N. 



Some Bird Friends. By Henry F. 

 PuLLEN. Published by the Free Lance 

 Publishing Company, Victoria, British 

 Columbia, Canada. Printed and com- 

 piled at the Oak Bay Print Shop, Vic- 

 toria. 30 pages. 20 illustrations from 

 original photographs. 



This attractive booklet is 'An intimate 

 introduction to a few of the common birds 

 of Western Canada,' and it should, as the 

 author hopes, help its readers to an inter- 

 est, or a further interest, in bird-life. Some 

 of Mr. Pullen's 'common birds,' such as 

 the White-crowned Sparrow and Pigeon 

 Guillemot, are rare or but names to most 

 easterners, and are pleasantly and inter- 

 estingly introduced. It is interesting to 

 know of a place where Crows nest several 

 hundred pairs to the acre, and that Sky- 

 larks have been successfully acclimatized 

 in British Columbia. A vireo is described 

 as 'a little larger than the flycatcher,' 

 which is, to say the least, vague, as the 

 flycatchers of British Columbia range 

 from under si.x to over nine inches in 

 length, and of course no vireo approaches 

 the latter size. The author has had the 

 good fortune of watching a 'Blue Grouse' 

 (meaning the local form of the Dusky 

 Grouse) hoot, but the answer came doubt- 

 less not from the bird's mate but from a 



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