Extinct Birds from Patagonia. 11 



shoulder-girdle seems more primitive, and it is difficult to 

 suppose that its condition is secondary and due to retrogres- 

 sion, or, in other words, that it is " pseudoprimitive." In 

 most of the Gruiformes the coracoid is short and stout, hut in 

 Cariama the bone is comparatively slender and the hyo- 

 sternal process reduced. 



The humerus in Phororhacos is much reduced, and is short 

 and stout. The upper end is not figured, but the lower is 

 remarkable for the obliquity of the distal border, the inner 

 margin being prolonged into a pointed process which extends 

 below the articular surfaces. The distal extremity is some- 

 what similar to that of the humerus of Aptornis, which also 

 is oblique, but without the acute internal angle. The con- 

 tinuity of the articular surfaces is probably merely the result 

 of reduction ; the same condition is well shown in the 

 humerus of Casuarius. 



The ulna (fig. 4, c) is short, stout, and compressed. The 

 tubercles marking the points of insertion of the secondaries 

 are strongly developed : these do not occur in the Ratitse. 

 There is a well-developed olecranon process. 



The metacarpal (fig. 4, a) is of the usual avian form, but as 

 in some Ratites the distal ends of metacarpals 2 and 3 are 

 not so firmly fused as in most Carinatse. 



The wings of Phororhacos, though so much reduced that the 

 power of flight was almost certainly wanting, were neverthe- 

 less powerful organs with apparently well-developed remiges. 

 Most likely they were employed as aids in running or 

 possibly in swimming, though the latter seems unlikely. 



Senor Ameghino unfortunately does not state upon what 

 evidence the various bones are referred to Phororhacos, but, 

 assuming that they are correctly determined'^, the comparison 

 given above shows that there is not much reason for 

 supposing that any close relationship exists between Phoro- 

 rhacos and the Gastornithidae, and the difference of the age 

 of the deposits in which they respectively occur renders such 

 relationship the more improbable. 



* I liave lately been informed that the hones described under the 

 name Fhororhacos injlatus nearly all belonged to a single individual. 



