THIRD ANNUAL MEETING 11 



there were those as small as the domestic fowl. Unfortunately, as already 

 stated, the number of specimens of birds from which laws may be 

 deduced are few, and while the earliest birds bear the imprint of char- 

 acters indicative of their approach to the Reptilia it is not decisively 

 revealed as yet out of which group they were derived. Though differ- 

 ing widely in outward appearance from dinosaurs there are structural 

 points of close similarity, and the one graduates so insensibly into the 

 other that it cannot be settled offhand just when or where the reptile 

 left oft' and the bird began. That is to say, there are connecting links 

 or generalized forms which leave one in doubt as to whether certain 

 specimens are avian reptiles or reptilian birds, as has been attested 

 many times by scientists at home and abroad. 



In attempting to systematize and classify these forms taxonomists 

 find so many structural characters in common between reptiles and 

 birds that they have iinited the two vmdcr one primary division called 

 the Sauropsida (reptile-like) just as fishes and batrachians are classified 

 under one general name Ichthyopsida (fish-like). 



The names Ornithoscelida (bird-legged animals, or Dinosauria), Ornith- 

 osauria (or pterodactyls), and Ornithes (birds), all derived from the 

 Greek word for bird, suggest close structural relationship. It can be 

 asserted confidently that the bird branch of the Reptilia began to diverge 

 from the true reptiles back in the Jurassic or possibly the Ti-iassic. At 

 any rate it is definitely certain that as early as the Jurassic birds were 

 differentiated, for at that time animals existed bedecked in feathers, 

 which since the days of Linnaeus has been accepted as the distinctive 

 badge of birds. This differentiation took place before the form of the 

 vertebrae had changed from the biconcave reptilian type to the saddle- 

 shaped articulations found in birds; before the caudal vertebrae had 

 become modified and changed from a functional to a shortened, inflex- 

 ible, nearly functionless series; and before the pelvis had developed 

 out of its separate elements into a solid piece. It was before birds 

 had beaks, for though possessing an avian skull the mouth of the earliest 

 birds was rather beast-like, an effect heightened by numerous teeth. 

 This was before birds had evolved into the wholly toothless modern 

 kind — that is, toothless as adults, but not wholly so as embryos. Cer- 

 tain embryonic birds furnished evidence of a toothed ancestry long 

 before the actual facts were known. 



SOME RELATIVES OP BIRDS 



Of the relatives of birds we have on the one side the highly inter- 

 esting and well specialized Pterosauria and on the other the ponderous 

 Dinosauria, the former specialized for flight, the latter for locomotion. 

 The pterodactyls, grouped together under the general title Pterosauria 

 or Ornithosauria (bird-lizard) came near being birds, but are barred 

 on the ground of possessing four digits in the hand, having the ischium 

 and pubis at right angles instead of parallel, and being without 



