GLASS II. AYES: OKDEIl 8. NATATOEES. 



303 



HAUNTS OF SEA-FOWL — THE GREAT NOUTUERN DIVEK, GUILLEMOTS, PUFFINS, ETC. 



pressed, and in others long and slender. The mandibles are sometimes sharp and smooth, some- 

 times furnished with denticulations or lamellce at the margins. The texture of the bill also va- 

 ries ; but these differences will be referred to in characterizing the families. 



Most of these birds live in societies, winch are often exceedingly numerous, inhabiting high 

 northern and southern latitudes. Many of them prefer rocky coasts, in the clefts and crannies of 

 Vvhich they lay their eggs, often on the bare rock, but generally selecting the most inaccessible 



