Classification of Birds 137 



ing in length the remainder of the spinal column. The 

 next group of Ratites, although it contained only the 

 Ostrich, Rhea, Emu, Cassowar)-, and Apteryx, he 

 shewed to be equivalent in anatomical coherence to the 

 third great group of Carinates, which incUides the vast 

 majority of living birds. In his arrangement of the 

 latter group, he laid most stress on the characters of 

 the bony structures which form the palate, and by this 

 simple means was able to la}- down clearly at least the 

 main lines of a natural classification of the group. 



Huxley's work upon birds, like his work in many 

 other branches of anatomy, has been so overlaid by the 

 investigations of subsequent zoologists that it is easy 

 to overlook its importance. His employment of the 

 skeleton as the basis of classification was succeeded by 

 the work of others who made a similar use of the mus- 

 cular anatomy, of the intestinal canal, of the windpipe, 

 of the tendons of the feet, and many other structures 

 which display anatomical modifications in different 

 birds. The modern student finds that all these new 

 sets of facts are much greater in bulk than the work of 

 Huxley, and it is easy for him to remain in ignorance 

 that they were all suggested and inspired by the method 

 which Huxley employed. He finds that further re- 

 search has supplanted some of Huxley's conclusions, 

 and it is easj' for him to remain in ignorance that the 

 conclusions themselves suggested the investigations 

 which have modified them. Huxley's anatomical work 

 was essentially living and stimulating, and too often it 

 has become lost to sight simpl}^ because of the vast 

 superstructures of new facts to which it gave rise. 



Closely associated with vertebrate anatomy is the 

 subject of geographical distribution. In 1857 the study 

 of this important department of zoology was placed on 



