rm-: r n. \ LA Mi's 



859 



nucleus like (lie rl;ius(ruin, i* tlioilRlit I" 1'eprcscnf :i .let.-irlietl portion of (hi- cortex prol.aMy 

 I'niin (In- region of the UUCU8. Con-idcnni; tins and it. cliu-C connection, it may I >e Concerned 



in tin. central portion oi tin. olfactory apparatus with ihc stna terminals, which tnu-, may be 



.-.oniewhat liomoloKoii.s In (lie Comix. 



The thalamus and hypothalamus. The external features of these portions of 

 (lie prosencephalon have been described in their natural plai-e. Inn inasmuch as they 

 contain I he chief relays ami connect ions between the telencephalon ami the divisions 



in- nervous .-vsteni below the prosencephaloii, the consideration of their internal 

 Structure baa been deferred till now. The principal grey masse* to be considered are 

 the thulamus and the hypothalanue nucleus. The structures of the metatlialamus 



l-'ic; 640 HORIZONTAL DISSK.I TIOV SHOWIN-O THE C.REY AND WHITE St MIST KM r OK 



I i i .1 M-I ..I.IIALON MKIXIW no: OOBPpa Cu.i.osrv AND THE HKLATIVK POSITION OK TUB 

 TH.VIAMENCKPHALON. (After l.aiulois and Stirlin 



AXTKliHHl 



/. 



i -I. I rs 

 \ ii. CAP- 

 SULE 1 1 ii 'I'll' I I'M. 



rni; ri<>.\ i 



I'll/H-ORA QVAD- 

 /.-/'. /..W.V.I 



CLA VA 



i-TXK-ri.ru rrxi-:.i ITS 



rrxt'Ti.r.s <ut.n-u.ifi 



and e|)ithalanius havr already been mentioned in their relations with the mesen- 



cephalon and the optic and auditory apparatus. 



The thalamus has upon its upper surface a thin stratum zonale of white sub- 

 stance, derived in part from the optic tract and in part from its own cells. Its 

 oblique lateral surface conforms to the inner surface of the internal capsule; its 

 vertical medial surface forms the lateral wall of the third ventricle, and below it is 

 continuous into the hypot lialamic (teirmental) region. Its dorsal surface shows a 

 middle, an anterior, and a posterior prominence or tubercle. The anterior tubercle 

 forms the posterior boundary of the interventricular foramen; the posterior tubercle 

 is the cushion-like 1 pulvinar which projects backwards over the lateral ireniculate 

 body and the brachium of the anterior quadrigeminate body. 



