THE PIGEON. 



259 



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

 lamina terminalis, (/./). 



If- 



t.ck 



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, infundibulum : m.o, 

 medulla oblongata : o.c, optic commissure: o.ch, optic chiasma : o.t, 

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

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

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



S 2 



