THE OLFACTORY APPARATUS 



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olfactory stria and extends backward directly into the tip of the 

 temporal lobe of the cerebral cortex (uncus), where the ventro- 

 lateral ends of the hippocampus and the hippocampal gyrus come 

 together; (2) the medial olfactory nucleus, including the sub- 

 callosal gyrus (Fig. 52, p. 119) and septum, which receive the 

 medial olfactory stria; (3) the intermediate olfactory nucleus, 

 which occupies the anterior perforated substance (Figs. 53, 105) 

 and receives the intermediate olfactory stria. These nuclei are 

 all important reflex centers, where olfactory stimuli are combined 



Olfactory bulb 



Lateral olfactory 

 (stria) 



Posterior parolfactory 

 sulcus 



Uncus (hippocampal 

 gyrus) 



Medial olfactory gyrus (stria) 

 Olfactory tract 



Limen insulae 



Anterior perforated 

 substance 



Hippocampal gyrus 



Fig. 105. Brain of a human fetus at the beginning of the fifth month 

 (22.5 cm. long), illustrating the olfactory centers visible on the ventral 

 surface. (After Retzius, from Morris' Anatomy.) 



with other sensory impressions, each nucleus having its own par- 

 ticular reflex pattern. The intermediate nucleus (also called 

 tuberculum olfactorium and by Edinger lobus parolfactorius) is 

 better developed in many other mammals than in man, and is 

 probably especially concerned with the feeding reflexes of the 

 snout or muzzle, including smell, touch, taste, and muscular 

 sensibility, a physiological complex which Edinger has called 

 collectively the "oral sense." This complex of muzzle reflexes 

 has probably played a very important role in the earlier stages 

 of the evolutionary history of the correlation centers of the 



