Zoological Society. 449 



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 Crow, 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 J 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 5 th 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 :J;th the size of the true olfactory nerve. 



" In the Turkey the olfactory branch of the 5th ner\T is about the 

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

 tory nerve, which is only about ^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 difference in the 

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

 of the head in these two species. In the Vulture there is a space 

 between the upper parts of the orbits in which the olfactory gan- 

 glions and nerves are situated, and the nasal cavity anterior to these 

 is of a much greater breadth and also longer, as well as exhibiting 

 internally a greater extent of pituitary surface, than in the Turkey. 

 In this bird the olfactory nerves are compressed within a narrow in- 

 terorbital space, which would not admit of the lodgement of gan- 

 glions; the olfactory nerves after passing through this space then di- 

 verge to the nasal cavity. 



" In the Goose the olfactory nerves are developed to the same size 

 as in the Vulture, and expand upon superior spongy bones of similar 



Phil. Mag, S. 3. Vol. 12. No. 76. Mai/ 1838. 2 Q 



