THE NERVOUS SYSTEM. 



551 



The stalk of the hemisphere has already been mentioned as including 

 that part where corpus striatum and thalamus meet. In this region, according 



v.m. 



FIG. 475. View of inside of the lateral wall of lateral ventricle of a human foetus at beginning 



of third month. His. 



Bb, bulbus olfactorius; C./., lateral limb of corpus striatum; C.m., medial segment (consisting of 

 the middle and inner limbs) of the corpus striatum. The furrow between these two parts 

 opens into the anterior olfactory lobe; hRl., posterior olfactory lobe; L.f., frontal lobe; L.o., 

 occipital lobe; Og., olfactory nerve; R. z., recessus infunclibuli; R. o., recessus (prae-?) opticus; 

 St., stalk of hemisphere (strio-thalamic junction); V.I., lateral ventricle; v.Rl.+Bb, anterior 

 olfactory lobe. 



to some, there is a, fusion of the striatum, the medial wall of the hemisphere and 

 the anterior part of the thalamus. According to others, the increase in bulk of 



Medial wall 



Chorioid plexus of 

 lateral ventricle 



Lamina terminalis 



Taenia thalami 

 Thalamus 



Habenula 



Trigonum subpineale 

 Cerebellum 



Myelencephalon 



Lateral ventricle 

 !audate nucleus (head) 



Medial wall 



Caudate nucleus (tail) 



Pineal body 



Median sulcus 



Mesencephalon 

 Fourth ventricle 



~^^^^ 



FIG. 476. Dorsal view of the brain of a 3 months' (45 mm.) human foetus. The dorsal part of each 

 cerebral hemisphere has been removed. Kollmann. 



this region is produced by a simple thickening of the walls, thus causing a flat- 

 tening out or shallowing of the grooves marking the junctions of striatum and 



