THE PIGEON. 



2S9 



and bounded in part by a thin plate of grey matter, the 

 lamina terminalis, {l.fj. 



Fig. 59. — Columba livia. The brain. A, dissected from the dorsal 

 aspect ; B, in longitudinal vertical section ( x 2). 



In A, the hemispheres are somewhat'displaced outwards, and the roofs 

 of the ri^ht lateral and optic ventricles are removed, as well as the 

 cerebellum and the velum interpositum. 



a. c, anterior commissure : cb, cerebellum : c.h, cerebral hemispheres : 

 c.s, corpus striatum : f.m, foramen of Monro ; inf, infundibulum : m.o, 

 medulla oblongata ; o.y, optic commissure : o.ch, optic chiasma : 0. 1, 

 optic lobes : olf, olfactory lobes : o.v, optic ventricle : p, peduncles of 

 cerebellum ; p. c, posterior commissure : fn, pineal body : tht, thala- 

 mencephalon : v.^, third ventricle : v.d,, fourth ventricle. 



S 2 



