THE PIGEON. 



259 



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

 lamina terminalis, (/./). 



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 right 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 t infundibulum : m.o, 

 medulla oblongata : 0.c, optic commissure: o.ch, optic chiasma : o.l, 

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

 cerebellum: p,c, posterior commissure : /, pineal body : the, thala- 

 mencephalon : ^.3, third ventricle : ^.4, fourth ventricle. 



S 2 



