6 BULLETIN 50, UNITED STATES NATIONAL MUSEUM 



vultures (subfamily Aegypiiuae, family Accipitridae) is merely a 

 superficial one, investigations of the anatomists having revealed 

 numerous important, not to say profound, differences in the internal 

 structure of the two groups, these involving not only the bony frame- 

 work, but the muscular system and other "soft parts." In short, 

 the general external resemblance is teleological or adaptive, both 

 groups performing the same service, that of scavengers, in the countries 

 they respectively inhabit, for which purpose certain external features 

 are similarly modified. 



The exact relationships of the Cathartae arc, however, somewhat 

 complex. It has been fairly clearly demonstrated that they are not 

 very distantly related to the Ciconiiformes, Pelecaniformes, and 

 Procellariiformes. One authority has even placed them in the 

 Coraciiformes (Anisodactylae) , on account of the similarity in the 

 arrangement of the plantar tendons, which is the same as in the 

 coraciiform superfamilies Bucerotes, Halcyones, and Coraciae, being 

 thus very different from that seen in the Falcones. Whatever may 

 be the significance of this agreement in one character with the aniso- 

 dactyle Coraciiformes, the true meaning of the more numerous 

 resemblances in structure to the other groups mentioned probably is 

 that the Cathartae are a much less specialized (or more generalized) 

 group than the true Falconiiformes and have not become differen- 

 tiated so far from the primitive stock from which the Ciconiiformes, 

 Pelecaniformes, and Procellariiformes have been developed. 



The suborder Cathartae includes only one living family, the Cath- 

 artidae, and two monotypic, extinct families, the Teratornithidae,'' 

 which displays features of both the Cathartae and the Falcones, but on 

 the whole is of cathartid affinities, and the Eocathartidae ^ forming a 

 distinct superfamily. It has the lachrymals fused with the frontals 

 and ectethmoids, and has a free communication of the nares with the 

 mouth and beak cavities. Other cathartid features are the enlarged 

 basisphenoid processes, the slight nasal depression, the short descend- 

 ing lachrymal processes, and the smooth contours of the cranium. 

 Falconid characters present are the high, compressed beak, with an 

 almost straight tomial edge, the high, short nares, the large lachry- 

 mals, and the solid interorbital septum. 



Family CATHARTIDAE: American Vultures 



>Vulturidae Bonaparte, Saggio Distr. Anim. Vertebr., 1831, 36 (includes true 

 vultures); Consp. Gen. Av., i, 1850, 9 (includes true vultures). — -Lesson, 

 Echo du Monde Savant, 9" an., vi, ser. 2, No. 44, 1842, col. 1030 (includes 

 true vultures). — Lilljebokg, Proc. Zool. Soc. London, 186G, 15 (includes 



« Miller, L. H., Univ. California Publ. Geol.. v, No. 21, 1909, 317. Wetmore, 

 A. O. U. Check-list, ed. 4, 1931, 429; Ann. Carnegie Mus., xxx, 1944, 58. 



