338 



web-footed birds, and lead us to survey the corresponding parts of the 

 skeleton in the ordinary birds of flight. 



Sufficient of the sternum remains for the rejection of the Gallinaceous, 

 and those Grallatorial and Passerine birds which have that bone deeply 

 incised ; and the field of comparison is thus restricted to such species 

 as have the sternum either entire or with shallow posterior emar- 

 ginations. Between the fossil and the corresponding part of the skeleton 

 of such birds, a close comparison has been instituted in regard to many 

 minor details and modifications, as, for example, the secondary muscular 

 impressions and ridges on the flat surface of the sternum ; its costal 

 margin and anterior angle ; the form and extent of the coracoid groove ; 

 the conformation of the sternal end of the coracoid bone, combined with 

 the form and relative size of the preserved articular extremities of the femur 

 and tibia : but, without recounting all the details of these comparisons, 

 it may be sufficient to state that, after pursuing them from the Sea-gull 

 and other aquatic species, upwards through the Grallatorial and Passerine 

 orders, omitting few of the species and none of the genera of these orders, 

 to which belong British birds approaching or resembling the fossil in 

 size, the greatest number of correspondences with the fossil were at 

 length detected in the skeletons of the Accipitrine species. 



The resemblance was not, however, sufficiently close to admit of the 

 fossil being referred to any of the existing native genera of Raptorial 

 birds. The breadth of the proximal end of the coracoid removed the 

 fossil from the Owls (Strigidre), and the shaft of the same bone was too 

 slender for the FalconidcE ; the femur and tibia were, likewise, relatively 

 weaker than in most of our Hawks or Buzzards. It is with the skeletons 

 of the Vultures that the fossil presents the closesl agreement. In the 

 small Turkey-Vulture (Cathartes Aura), for example, besides the same 

 general form and proportions of the bones, so far as they exist in the 

 fossil, there is the same degree of development, and the same direction 

 of the intermuscular ridge on the under surface of the sternum, which 

 divided the origins of the first and second pectoral muscles. The outer 

 angle of the proximal end of the coracoid is produced in the same degree 

 and form, and a similar intermuscular ridge is present on the anterior and 



