92 SYLVAN SECRETS. 



From this slight sketch of what the old 

 rocks tell about birds, we see that, so far as 

 fossil remains teach anything, they teach us 

 that the oscine form was the last to appear in 

 the succession of structural changes in the 

 bird's general physique. This is as far as we 

 can go in the direction of mere development 

 of form, by the light of anatomy, considering 

 fossil skeletons merely as such. 



Let us turn r w and take a quick glance 

 over the evident :>f voice development dis- 

 coverable in the kinship between birds and 

 reptiles. 



Professor Huxley, in one of the most ad- 

 mirable of his great contributions to scien- 

 tific taxonomy, has classed the birds and the 

 reptiles together, or rather grouped them un- 

 der one head, as constituting- a primary divi- 

 sion of the vertebrates. He has based this 

 classification on many points in which, on one 

 hand, birds and reptiles agree anatomically 

 and physiologically, and on their variance 

 from mammals in as many points on the 

 other hand. Indeed, the kinship between 

 birds and reptiles is still very strong, even af- 

 ter the immense development of the bird form 

 and the comparatively slight modification of 

 most reptile forms which have come about 

 since the time of Archseopteryx and the dino- 

 saurian animals of the triassic rocks. 



We may assume, then, that the develop- 

 ment of the vocal organs in birds has been, in 

 some measure, apace with or dependent upon 

 the departure of the bird form from that of 

 the reptile. 



Our present existing reptiles are almost de- 

 void of voice proper. Some of them can make 

 certain dismal, guttural groans or croaks, 

 others can utter shrill, discordant sounds; 



