34 



and placed it in a field ; in a few minutes a vulture alighted near it 

 and directly proceeded to attack it, but finding no eatable food he at 

 length quitted it. And he further relates that a dead dog was con- 

 cealed in a narrow ravine twenty feet below the surface of the earth 

 around it and filled with briers and high canes ; that many vultures 

 were seen sailing in all directions over the spot but none discovered 

 it. I may remark upon the above experiments that in the first 

 case the stag was doubtless seen by the birds, but it does not follow 

 that they might not also have smelt the hide, although inodorous to 

 the human nose ; in the second case, the birds had undoubtedly 

 been attracted by smell, however embarrassed they might have been 

 by the concealment of the object which caused it. I have in many 

 hundred instances seen the vulture feeding upon small objects under 

 rocks, bushes, and in other situations where it was utterly impos- 

 sible that the bird could have discovered it but through the sense of 

 smell ; and we are to recollect that the habit of the vulture is that 

 of soaring aloft in the air, and not that of foraging upon the ground." 

 Mr. Sells's communication was accompanied by the following let- 

 ter from Mr. Owen, addressed to the Secretary, W. Yarrell, Esq. 



" Dear Sir, — I received the heads of the John Croir, which I sup- 

 pose to be the Vultur aura or Turkey Buzzard, and have dissected 

 the olfactory nerves in both ; as also in a Turkey which seemed to 

 me to be a good subject for comparison, being of the same size, and 

 one in which the olfactory sense may be supposed to be as low as in 

 the Vulture, on the supposition that this bird is as independent of 

 assistance from smell in finding his food as the experiments of Audu- 

 bon appear to show. There is, however, a striking difference be- 

 tween the Turkey Vulture and the Turkey in this part of their organi- 

 zation. The olfactory nerves in the Vulture arise by two oval ganglions 

 at the anterior apices of the hemispheres from which they are con- 

 tinued 1^ line in transverse diameter, and 2 lines in vertical diameter, 

 and are distributed over well-developed superior and middle spongy 

 bones, the latter being twice the dimensions of the former. The 

 nose is also supplied by a large division of the supraorbital branch 

 of the 5th pair, which ascends from the orbit, passes into the nose 

 crossing obliquely over the outer side of the olfactory nerve, extend- 

 ing between the superior spongy bone and the membrane covering 

 the middle spongy bone, then descending, and after supplying the 

 inferior and anterior spongy bone escaping from the nasal cavity to 

 supply the parts covering the upper mandible. This olfactory branch 

 of the 5th pair is about :|:th the size of the true olfactory nerve. 



" In the Turkey the olfactory branch of the 5th nerve is about the 

 same size as in the Vulture, and is superior in size to the true olfac- 

 tory nerve, which is only about J-th the size of that in the Vulture. 

 The olfactory nerve does not form a ganglion at its commencement, 

 but is continued as a small round chord from the anterior apex of 

 each hemisphere, and is ramified on a small middle spongy bone, 

 there being no extension of the pituitary membrane over a superior 

 turbinated bone as in the Vulture. Indeed the difi^erence in the 

 development of the nasal cavity is weU marked in the different forms 



