8 BULLETIN 5 0, UNITED STATES NATIONAL MUSEUM 



longer than the inner; hallux elevated, nonfunctional (not adapted 

 for grasping), about equal in length to basal phalanx of inner toe; 

 all the anterior toes connected at base by a well-developed web; tarsi 

 and greater part of toes covered with small, nearly circular, scales, 

 these becoming obsolete, or nearly so, on the upper portion of tarsus; 

 claws short, blunt. 



Nest, none, the eggs being deposited on the ground or in a cavity 

 of a t'-ce or stump or among rocks; eggs, one or two, much more 

 elongate than those of other Falconiformes (Falcones), plain whitish 

 or spotted, the inner shell showing a yellow or greenish-yellow trans- 

 lucence when viewed against the light.* 



The American vultures are birds of powerfid and graceful flight 

 and represent probably the most perfect type of soaring bird; indeed 

 much the greater part of their time, when not at rest, is spent "soaring 

 on bouyant wing," sm-veying the ground far below for the carrion 

 or offal which constitutes their food. At other times they sit, perched 

 upon some tree top or other elevated position, with motionless wings 

 fully outstretched, in the manner of the cormorants and anhingas.^ 



The question whether the American vultures are able to discover 

 their food by the sense of smell is a debatable one, for, though it has 

 been argued, pro and con, the evidence of either side is not entirely 

 convincing. Without desiring to enter into a discussion of the sub- 

 ject, I venture to remark that one important fact seems to have been 

 overlooked in connection with the matter, namely the obviously 

 great difference in the development of the olfactory organs in the 

 different genera. These are more highly specialized in the genus 

 Cathartes than in the other genera; and from numerous observations 

 I am fully convinced that the birds of that genus do, to a great extent, 

 utilize their keen sense of smell for the discovery of their food. On 

 the other hand, my conviction is equally strong that Coragyps urubu 

 depends mainly if not exclusively on its keen vision for that purpose. 

 Carefully conducted experiments, however, are necessary before the 

 question can be settled beyond dispute. (R. R.) 



The Cathartidae include the largest birds of flight now existing, the 

 famed condor of the Andes (Vultur gryphus) and the equally large 

 California species (Gymnogyps californianus) being among its mem- 

 bers. Some existing carinate birds exceed these in weight, and a few 

 (the large albatrosses, for example) equal them in extent of wings, 

 but none is quite their equal in weight and spread of wing combined, 



' In the Accipitridae (except Gypaetus and Neophron) the color of the eggshell 

 when similarly viewed is green; in the Falconidae, in Gypaelus and Neophron, 

 and in the Sagittariidae, it is reddish yellow. 



^ As if in confirmation of their not too distant relationship to the Pelecani- 

 formes, as indicated by anatomical similarities in the two groups. 



