. The structure and life of birds . or part,the cerebellum (cb, Fig. 30), will be easily dis-tinguished ; in contact with it at their hinder ends aretwo large bodies that make up nearly the whole of thetop of the brain. These are the cerebral hemispheres,the larger development of which makes a birds brain sodifferent from a reptiles (c/i). In them all the higherfaculties reside. If they are severely- injured or re-moved, there is no more intelligence, memory, orvoluntary movement. There is only what is calledreflex action such as is called forth in a hydra or acoral animal when food touches it
. The structure and life of birds . or part,the cerebellum (cb, Fig. 30), will be easily dis-tinguished ; in contact with it at their hinder ends aretwo large bodies that make up nearly the whole of thetop of the brain. These are the cerebral hemispheres,the larger development of which makes a birds brain sodifferent from a reptiles (c/i). In them all the higherfaculties reside. If they are severely- injured or re-moved, there is no more intelligence, memory, orvoluntary movement. There is only what is calledreflex action such as is called forth in a hydra or acoral animal when food touches its tentacles ; they closeupon it without consciousness or intention on the 1 See Coues Field and General Ornithology, p. 257 andonward. nS THE STRUCTURE AND LIFE OF BIRDS chap animals part. In the same way when the eyes winkat a sudden flash of light, we call the action Frog, whose cerebral hemispheres are no longerin their place, will move its foot when it is irritated :of thus much, lower parts of the brain are Fig. 30. — Pran of Pigeon (after Parker); A from above ; P, front below; C fromleft side(x2); cb cerebellum; cerebral hemispheres; Medulla Oblongata;n roots of cerebral nerves ; o 1. optic lobes ; olf olfactory lobes ; pn pineal body. If the whole brain is removed and only the spinalcord is left, even breathing will not continue. Whenthere is much intellectual power, as in man, thehemispheres arc highly convoluted—, they are amass of folds and wrinkles. When the birds skull is vi FORM AND FUNCTION 119 removed, one is struck with the smoothness of thebrain. The olfactor)- lobes (olf.), in which lies the sense ofsmell, arc small cone-shaped objects which projectfrom underneath the front end of the hemispheres,their smallness suggesting that birds depend little onthis sense. Formerly it was thought that vultures scented the carrion from afar, but Darwin showedby experiment that this was not the case. He wrappedsome meat in paper, and
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