IHE 
AMERICAN NATURALIST 
Vor. XXXIV. October, 1900. No. 406. 
RECONSIDERATION OF THE EVIDENCE FOR A 
COMMON DINOSAUR-AVIAN STEM 
IN THE PERMIAN. 
DINOSAUR CONTRIBUTIONS, NO. 4. 
HENRY FAIRFIELD OSBORN. 
Tur relation of dinosaurs to birds has been one of the most 
attractive problems of comparative anatomy during the thirty- 
seven years which have elapsed since Gegenbaur’s observation 
that the tibiotarsus of Compsognathus, one of the smallest car- 
nivorous dinosaurs, closely resembles that of the bird. 
Since a number of new avian resemblances have recently 
been discovered among dinosaurs, it seems important to recon- 
sider this much debated problem. 
I. Avian RESEMBLANCES IN CARNIVOROUS BIPEDAL DINOSAURS. 
We owe to Fürbringer (88, p. 1592) a valuable historical 
summary of the literature and progress of opinion. The recog- 
nition of avian characters among dinosaurs has been generally 
1 Presented before the American Association for the Advancement of Science, 
Section Zoólogy, June 27, 1900. 
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