THE MAMMALIAN NERVOUS SYSTEM 107 



1158-1161, Fig. 1002, p. 1163, Figs. 1004-1006, pp. 1165-1167; 

 Rauber-Kopsch ('07), Fig. 688, p. 625; Fig. 624, p. 543. 



Master now, by the aid of text-books and diagrams, the ol- 

 factory system and its connections and relations as seen in the 

 sheep which is the same in plan as in the human brain. Review 

 the entire dissection, tracing the course of olfactory impulses 

 through the reflex pathways and centers of the basal regions from 

 the nose to the epithalamus and hypothalamus and through 

 the cortical pathways to the hippocampus and thence again to 

 the epithalamus and hypothalamus. This gives a schematic 

 picture of the workings of the entire rhinencephalon. This 

 should be done before further work is undertaken and an analysis 

 of these pathways fully written up. 



131. Now cut through the genu of the corpus callosum forward 

 and downward toward the olfactory bulb, thus opening up the 

 anterior horn of the lateral ventricle, which in the sheep is 

 directly continuous with the ventricle of the olfactory bulb. 

 (In the human brain the ventricle of the olfactory bulb is 

 obliterated in the adult.) 



132. Beginning now in the gyrus hippocampi at the most 

 lateral border of the lateral ventricle, note the positions of the 

 stria terminalis (stria or taenia semicircularis), plexus chorioideus 

 of the lateral ventricle and tail of the caudate nucleus. Follow 

 the last three medially and anteriorly, noting carefully their 

 relationships to each other and to the hippocampus, until the 

 anterior end of the head of the caudate nucleus is reached near 

 the region of the anterior perforated space. The stria ter- 

 minalis can be traced forward into the anterior commissure. 

 Tracing the stria terminalis backward into the temporal lobe 

 it will be seen to enter the anterior tip of the gyrus hippocampi, 

 where it ends in a small deep gray mass, the nucleus amygdalce. 

 See Cunningham ('15), Figs. 539, 563; Herrick ('15), Figs. 76 

 and 121; Morris ('14), Figs. 658, 688, 691, pp. 834, 875, 878 

 respectively; Piersol ('13), see references under Section 130; 

 Quain ('09), Figs. 228, 233, 294, pp. 224, 229, 294 respectively. 



133. Draw the dissection at this stage, as seen from above, 

 showing the form of the lateral ventricle and the structures 

 which form its walls (cf. Burkholder ('12), Plates XIII- 

 XVI). 



