PEDIGREES AND FAMILY TIES. 215 



Another ancient form allied to the geese is 

 gasiornis, an extinct goose-like bird larger than 

 an ostrich. 



Next under consideration must come a series 

 of forms, all of which are probably more or less 

 nearly allied. They may be divided into about 

 four great groups as follows : — 



(1) The gannets, cormorants, darters, frigate- 

 birds, pelicans and boatswain birds, (2) the storks 

 and herons, ibises and flamingoes, (3) the hawks, 

 eagles and vultures, and (4) the cranes, rails, 

 plovers, gulls, auks, pigeons and sand-grouse. 



The birds-of-prey seem to claim affinity with 

 the crane-tribe on the one hand, and the stork- 

 tribe on the other. If they had a leaning more 

 one way than another perhaps it is towards the 

 storks. Amongst other things, like the storks, 

 they nest in trees rather than on the ground, 

 and their young are for a long time helpless. 

 Some doubt whether the vultures of America 

 should really be included amongst the birds-of- 

 prey at all, holding that they are really much 

 more closely allied to the storks. 



The most aberrant bird of prey, after American 

 vultures, is the secretary bird of Africa, which, 

 amongst other things, has acquired legs of great 

 length. The Osprey was once supposed to re- 

 semble owls in some respects, and on this account 

 was regarded as an aberrant type connecting owls 

 and hawks, but it is now certain that it has no 

 affinity whatsoever to these. 



The typical cranes scarcely need description. 

 Yet, many constantly confound the common heron 

 of our river sides and marshes with the 'crane. 



