EXTINCT PATAGONIAN FLIGHTLESS BIRDS 



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EXTINCT PATAGONIAN FLIGHTLESS BIRDS 

 Group STEREORNITHES 



Although their intercalation between the tinamus and the ostrich-like birds 

 somewhat interferes with a proper sense of the connection of those two groups, it 

 is necessary to mention here an assemblage of giant flightless birds, which were 

 abundant during the Miocene Tertiary in Patagonia and parts of Argentina. 

 These Stereornithes, as they are called, certainly cannot be included among the 

 modern flightless group of giant birds, and it is uncertain whether they can claim 

 a place with the preceding orders in the great subclass of Carinatte; so that they 

 must, accordingly, be allowed to constitute a group by themselves, of which the 

 exact serial position cannot yet be fixed. Attaining gigantic dimensions (the tibia 



SIDE VIEW OF SKULL OF GIANT FLIGHTLESS PATAGONIAN BIRD (PhororhachlS) . 

 (About two-fifths natural size.) 

 (From Ameghino.) ' 



of one species being upward of thirty inches in length) these Patagonian birds are 

 especially characterized by the great relative size and remarkable form of their 

 skulls. In one species, for instance, the lower jaw measures twenty-one inches in 

 length, and is of extraordinary massiveness; while in another, although shorter, this 

 massiveness is still more exaggerated. The skull is characterized by the great depth 

 and compression of the upper mandible of the beak, which terminates in a descend- 

 ing hook, toward which the extremity of the lower mandible gently ascends. The 

 nasal apertures (A 7 ") are pierced very high up on the sides of the skull, and have no 

 partition between them, and the lower mandible is truncated posteriorly, and has its 

 two branches united by a very long symphysis. A feature in which these birds differ 

 from the ostrich group is to be found in the circumstance that the quadrate bone 

 (i) articulates with the rest of the skull by two heads at its upper extremity, as in 

 ordinary flying birds. In the leg bones the tibia has a bony bridge at it's lower end 

 for the protection of the extensor tendons, and the first toe was generally present. 



