148 BIRDS. 



trils developed; no gular pouch. ^\ r ings very long and 

 pointed. Tail well developed; altricial; powers of flight 

 remarkable; food chiefly fishes. There are two families, 

 LaridcB, below described, and frocellciridcBj the Petrels, 

 which we here omit, all our numerous representatives 

 being strictly maritime. 



FAMILY LXITL LARID^E. 



(The Gulls.) 



Long- winged birds, with the nostrils not tubular; 

 bill various. Hind toe small and elevated, but less so 

 than in the Petrels. General color usually white, with 

 a darker mantle of a pearly bluish tint, and commonly 

 with some black markings. Sexes alike in color, but the 

 plumage varying much with age and season. Genera 

 about twelve (Coues), sixty (European authors); species 

 ninety; abounding about all large bodies of water. Of 

 the genera admitted below, Pagophila^ Rissa, and 

 C kroecocephahis may properly be considered as sections 

 of Lams, while Gelochelidon and Thalasseus are perhaps 

 sub -genera under Sterna. 

 * Bill hooked (epignathous) rarely not hooked, and the tail even. 



f Bill with a sort of cere ; middle tail feathers exserted ; Jasgers. 

 (LESTRIDIN^E.) .... STERCORARIUS, 1. 



f f Bill not cerecl ; general color usually white with a darker 

 mantle. Gulls. 



a. Hind toe rudimentary, without a developed claw. RISSA, 3. 

 an. Hind toe perfect, provided with a claw. 

 b. Tail even. 

 c. Tarsus black, rough ; webs incised ; plumage white. 



PAGOPHILA, 4 



cc. Tarsus not black ; lower plumage white in adult. 

 d. Head white if dark below, head not whitish (spe- 

 cies of large size ; never rosy-tinted below ; the 

 head never with a dark hood.) . LARUS, 2. 



