190 



Proceedings of the Royal Irkh Academy. 



Fleclimf has recently described in the braia of an eight months' 

 foetus, and which passes from the internal geniculate body to the 

 anterior transverse temporal gpi perforating the putamen in its coui'se. 

 This bundle was medullated before those of the fillet, which are con- 

 tributed to the posterior coi-pora quadrigemina. 



The above retro -lenticular group descended with the capsular 

 fibres, and was found to be distributed in the following ways. Many 

 of its fibres entered the optic thalamus (see d, 3. fig. 4), and of these 

 some were not traceable further. Others traversed this body, and 



d./. 



Vertical section tlirough brain of maiinoset vii., posterior to 



d. 1. and d. 2. as in fig. 5. 



d. 3. external capsule. 



d. I/., and 8. anterior commissure. 



d. 5. corpus callosum. 



d. 6. degenerations extending into opposite temporal lobe. 



d. 7. opposite internal capsule. 



appeared near the sui'face at a sulcus external to the anterior corpus 

 quadiigeminus" (see fig. 4.) Some of these latter entered the anterior 

 tubercle ; the remainder were continued backwards to enter the posterior 



1 Flechsig, P., Zur Anatomie des vord. Seb-bugelstiels des Cingulum u. dev 

 Acusticus-Balin. Neui-ol. Centralb. xvi. 7, p. 290. 



- Cf . Boyce, " Contrib. to the Study of : I. Some of the Decussating Tracts of the 

 Mid- and Inter-brain ; II. Of the Pyramidal System in the Mesenceph. and Bulb." 

 Phil. Trans, ser. B. vol. 188, pp. 218, 219. 



