jy BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



cets and stilts), Rynchopidae (skimmers), Sternidae (terns), Laridae 

 (gulls), Stercorariidae (skuas and jaegers), and Alcidae (auks). 



Part IX, issued October 2, 1941, contained the Gruiformes with the 

 families Gruidae (cranes), Rallidae (rails, gallinules, and coots), Helior- 

 nithidae (sun-grebes), and Eurypygidae (sun-bitterns). 



Part X (the present part) contains the Galli formes, with the families 

 Cracidae (curassows, guans, and chachalacas), Tetraonidae (grouse and 

 ptarmigan), Phasianidae (American quails, partridges, and pheasants), 

 Numididae (guineafowl), and Meleagrididae (turkeys). 



Part XI, now ready for press, will contain the Falconi formes, with the 

 families Cathartidae (New World vultures), Accipitridae (hawks, kites, 

 buzzards, eagles, and harriers), Pandionidae (ospreys), and Falconidae 

 (falcons, caracaras, and laughing falcons). 



Part XII, now in course of preparation, will contain the Anseri formes 

 (ducks, geese, and swans) ; the Ciconiiformes, with the families Ardeidae 

 (herons, bitterns, etc.), Cochleariidae (boatbills), Ciconiidae (storks and 

 wood ibises), Threskiornithidae (ibises and spoonbills), and Phoenicop- 

 teridae (flamingoes) ; the Pelecaniformes, with the families Phaethonti- 

 dae (tropicbirds), Pelecanidae (pelicans), Sulidae (boobies and gan- 

 nets), Phalacrocoracidae (cormorants), and Fregatidae (man-o-war- 

 birds) ; the Procellariiformes, with the families Diomedeidae (alba- 

 trosses), Procellariidae (shearwaters and petrels), and Hydrobatidae 

 (stormy petrels) ; the Colymbiformes (grebes) ; the Gaviiformes (loons) ; 

 the Sphenisciformes (penguins) ; and the Tinamiformes (tinamous). 



In the ten volumes thus far published there have been treated in detail 

 (that is, with full descriptions and synonymies), besides the families above 

 mentioned and higher groups to which they belong, 695 genera and 2,756 

 species and subspecies, besides 237 extralimital genera and 638 extralim- 

 ital species and subspecies whose principal characters are given in the 

 keys and whose principal synonymy is given in footnotes. 



For the privilege of examining, or for the loan of, specimens needed in 

 the preparation of the present volume acknowledgments are due to the 

 authorities of the Academy of Natural Sciences of Philadelphia; the 

 American Museum of Natural History, New York ; Carnegie Museum, 

 Pittsburgh ; Chicago Natural History Museum ; Museum of Comparative 

 Zoology, Cambridge; National Museum of Canada, Ottawa; Royal On- 

 tario Museum of Zoology, Toronto ; Museum of Vertebrate Zoolog>% 

 Berkeley ; University of Michigan Museum, Ann Arbor ; Cornell Uni- 

 versity Museum, Ithaca; California Academy of Sciences, San Francisco; 

 California Institute of Technology, Pasadena ; Princeton University Mu- 

 seum ; U. S. Fish and Wildlife Service, Washington, D. C. ; Museum of 

 Birds and Mammals, University of Kansas, Lawrence ; British Museum 

 (Natural History), London; Museum d'Histoire Naturelle, Paris; Na- 

 turhistorisches Museum, Vienna; Natural History Museum, Leyden; 



