26 LAND-BIRDS AND GAME-BIRDS 
North American birds. The Natatores include various sea- 
birds, the swans, geese, ducks, terns, gulls, pelicans, petrels, 
and cormorants, and form about one-fourth of our fauna. The 
Insessores include all the typical land-birds, 377 of the 635 
North American species admitted in Dr. Coues check-list, and 
more than one-half of about 300 species, known to have oc- 
curred in Massachusetts. In this volume I have, with the 
exception of the game-birds, treated the typical land-birds 
only. The Jnsessores contain five orders, described in the 
following chapters. 
