390 THE STRUCTURE AND LIFE OF BIRDS cH. xv 
The Partridge lays at least twelve eggs—-sometimes 
over twenty—the Snipe only four. 
This chapter which, as I have said, is only intended 
to give some idea of the general principles of classi- 
fication, must now come to an end. Those who wish 
to make a study of the subject are referred to the 
books that deal specially with it. 
SOME OF THE LITERATURE OF THE SUBJECT. 
Elements of Ornithology. St. George Mivart. [The best 
book for beginners. ] 
Classification of Birds. Henry Seebohm. 
Bronn’s Zhzer-Reich, vol. “ Aves.” Dr. Gadow. 
Vertebrate Anatomy. Professor Huxley. 
