on classification of Passeres, [467]
absent in Apterygidae, [39];
absent in Dinornithidae, [42];
absent in Rheidae, [30];
absent in Struthionidae, [27];
ancylosed with sternum in Gruidae, [252];
in Otididae, [261];
in Heliornithidae, [267];
coalesces with coracoids in Fregata, [72];