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C. Judson Herrick 



visions, between which it lies. It has fibrous connections with the 

 hypothalamus, habenula and área dorsalis. Like the área olfactoria 

 lateralis, it may be functionally connected with the área somática which 

 lies behind it, as is known to be the case in some higher brains. 



5. The área somática occupies the ventro-lateral surface of the 

 contracted posterior part of the telencephalon médium and its gray 

 matter is directly continuous with that of the thalamus. The importance 

 and significance of this área were first recognized by Johnston, who des- 

 cribes the following fiber tracts related with it (fig. 16): i) Ascending 



crol. 



f. med.t.' 



com.ant 



Fig. 15. — Diagram of the forebrain of Acanthias seen from the left side, illus- 



trating some of the connections of the área olfactoria. Based on figures and des- 



criptions of Johnston (191 1). 



fibers from the optic and other exteroceptive or somatic centers of the 

 dorsal part of the thalamus; these are thalamic radiations corresponding 

 with the thalamo-frontal tracts which I have described in Amphibia. 

 2) Descending fibers from the área somática to the ventral part of the 

 thalamus and pedunculus cerebri (somatic projection tract of Johnston). 

 These two systems comprise an important part of the lateral forebrain 

 bundle of Amphibia and Reptilia. 3) An olfacto-somatic correlation 

 tract between the área somática and the área olfactoria lateralis. 4) A 

 connection with the habenula (tractus taeniae, Johnston). 5) Commissu- 

 ral fibers (corpus callosum, Johnston) connecting the \.\\o somatic áreas 

 and crossing far forward in the dorsal part of the commissura dorsalis. 

 The relations of the área somática of selacliians are very similar to 

 these in Acipenser and Petromyzon and much more clearly defined. The 



