1 1 *ib9 J 



Short thick bills, with a callus ex-' 



irt thick bills, with a callus ex- "1 

 tending up the forehead; toes f iy P * 

 furnished on their fides with | ^^- '^•^°" 39^ 

 broad fcalloped membranes - J 



Strait, flrong, fharp pointed bills i"^ 



toes furniflied on their fides I 5f p U 



with broad plain membranes j f" ' ^^ ^^ 393 



no tail -------J 



III. 



Long, flender, and comprelled bill i YT a r ** 



turned upwards - - - - j" * ^ 399 



No back toe - - * -- * - *• XII. Auks 401 



Strong, ftrait, fiiarp pointed bills XIII. Divers 41^ 



Strong bills hooked at the end ; an "^ 



angular knob on the lower man- C XIV. Gulls 416 

 dible ; narrow oblong noftrils J 



Strait, flender, fharp-pointed bills : 7 yu" T » 



forked tails ----- -| ^^- "^ ^''"^ 425 



Strong bills hooked at the end ; t 



tubular nofliils: fharp procefs C XVI. Petrels 431 

 inftead of the back toe - - j 



Long flender bills hooked at the-) vTrrr ^ /> j 

 ends, and the edges furnifhed C XVII. Goofanders 

 with numerous fmall teeth - \ 43° 



Flat broad bills - -' •- - - - XVIII. Ducks 440 



Each of the four toes conne6led by ") -vrrv o \ ^ n 



'""^■^J^m'^^'^l^''- . ^.- - _/ fXIX.Corvorants476 



* 1,;^ Explanation 



