37? ZOOTOMY. 



LXIV. Cut tnrough the three commissures of the 



third ventricle, and press the thalami gently apart. 



Note: 



528. The infundibulum (inf), a funnel-shaped cavity, 



into which the third ventricle is continued below, and 



which, after the removal of the pituitary body, opens by 



the small aperture already noticed on the base of the brain 



(see § 485). 



o.ch.^W--pti/\m.co. p.m. i,.vn 

 f,fo. ^•^ch? 



Fig. 72. — Lepus cuniculus. Longitudinal vertical section of the 

 brain (nat. size). 



a. CO, anterior commissure : p.fo, anterior pillar of fornix, supposed 

 to be seen through optic thalamus : h.fo, body of fornix : cb, cerebellum, 

 showing arbor vitae : c.c, crus cerebri : c.li}-, cerebral hemisphere : c.K-, 

 its temporal lobe : c.nia, corpus mammillare : cp.cl, corpus callosum : 

 f.m, foramen of Monro : inf, infundibulum -. ly, lyra ; m.co, middle 

 commissure : m.o, medulla oblongata : o.ch, optic chiasma : o.O-, natis : 

 o.P, testis : olf, olfactory lobe : f.co, posterior commissure : pn, pineal 

 body : fd.pii, its peduncle : pty, pituitary body : sp.lii, septum lucidum : 

 vl.ip, velum interpo?ituin ; v.vn, valve of Vieussens : "-.4, fourth 

 ventricle : //, optic nerve. 



529. The lamina terminalis, or lamina cinerea (l.t), 

 the thin vertical anterior wall of the third ventricle. 



530. By carefully scraping away the inner surface of one 

 of the optic thalami, trace the anterior pillar of the 

 fornix {p.fo), which, after curving over the foramen of 



