494 PROCEEDINGS OF THE ACADEMY OF [1898. 



tion, cannot be brought in close contact; and yet, their sterna, 

 according to Mr. Blanchard, much resemble each other. It is evi- 

 dent, therefore, that the whole structure of a bird and its correspond- 

 ing habits may be profoundly modified, and yet the sternum may 

 undergo the important changes, while the general organization and 

 habits are but little altered." So much for the value of single 

 anatomical systems in avian taxonomy, and so much for the value 

 of single characters in any system. Now as to the value of osteology 

 as a whole in the classification of birds, no ornithotomist or classifier 

 of this group of vertebrates will for a moment doubt. Employed in 

 its entirety the osseous system of Aves stands far in advance of any 

 other in settling the question of affinities and affording characters in 

 classification. It has been almost entirely through our studies of 

 the fossil skeletons of birds that we have been enabled to fix their 

 origin in time, or to link them with their extinct reptilian ancestors. 



The researches of the Parkers in the development of the embryo- 

 logical skeleton of birds ; of Huxley in the skull ; and the labors of 

 Macgillivray, Nitzsch, Merrem, De Blainville, L'Herminier, Cuvier, 

 St. Hilaire, Gervais, Blanchard, Eyton, Owen, Garrod, Forbes, Fiir- 

 bringer, Gadow, Lucas, Beddard, and many others upon the general 

 skeleton ; while the study of palseontological osteology by Milne- 

 Edwards, Cope, Marsh, and their colleagues in the same field, would, 

 when taken in the aggregate go far toward establishing a natural 

 classification, or rather toward indicating the true affinities of birds. 



Still in face of all this we must believe, that osteology is by no 

 means an all-sufficing guide, nor has it been in the mind of the pres- 

 ent writer in his attempts to discover the true kinships existing 

 among birds ; their systematic positions ; and the places the vari- 

 ous natural groups should occupy in any scheme of classification. 



On the contrary the aim has been to examine with care into the 

 results of the anatomical and general biological investigations of 

 birds by whomsoever they may have been undertaken and published, 

 so long as those researches seemed to have any bearing upon the 

 solution of the true affinities of the class. With this in view a very 

 wide field of literature has been considered, and the works of a great 

 many authors examined. All through this, osteology has held the 

 main place, but constantly subject to subordination when factors 

 drawn from other anatomical systems or from the general life-his- 

 tories of the bird-groups, possessed beyond all doubt greater weight 

 and significance. 



