VI FORM AND FUNCTION 119 
removed, one is struck with the smoothness of the 
brain. 
The olfactory lobes (olf.), in which lies the sense of 
smell, are small cone-shaped objects which project 
from underneath the front end of the hemispheres, 
their smallness suggesting that birds depend little on 
this sense. Formerly it was thought that vultures 
“scented the carrion from afar,’ but Darwin showed 
by experiment that this was not the case. He wrapped 
some meat in paper, and put it near some condors 
that were tethered in a garden. When it was only a 
yard off him, an old cock bird “looked at it for a 
moment with attention, but then regarded it no more.”! 
It was pushed closer and closer till at last it touched 
his beak, when the paper was “torn off with fury.” 
The optic lobes (0.].) are many times larger—two 
rather egg-shaped bodies at the sides of the brain, 
partly below the hemispheres. Their size suggests, 
what is really the case, that the vulture finds his food 
by sight. His eyes sweep the whole country round 
as he flies, and when he swoops down upon a carcass 
he is seen by numbers of others who quickly follow. 
Towards the back of the brain between and under the 
hemispheres lies a small oval object called the pineal 
gland or body (pn.). What may now be its function, 
if it has any, is unknown. Formerly it is believed to 
have been a central eye. In the bird’s skull, in which 
the fusion of bones is so marked a characteristic, we 
should not expect to find any external evidence of 
this rudimentary organ. But in lizards a hole in the 
1 Darwin’s Journal of Researches, chap. ix. (p. 133, Minerva 
ed.). 
