262 University cf California Publications in Anatomy [Vol. 2 



Fig. 57, Experiment II. A portion of the preceding figure under higher 

 magnification showing the upper lip of the calcarine fissure. It shows the 

 degenerated afferent visual fibers, black lines and dots, entering the striate 

 cortex marked with number 17 and containing a dotted intracortical stripe. 

 The first thing to be noted is that the visual fibers wlien still in the white sub- 

 stance keep close to the striate cortex, lea\nng other portions of that substance 

 close to the nonstriate cortex (marked with number 18) entirely free. The 

 exact coincidence of the boundaries of the cortex reached by degenerated fibers 

 and of the striate cortex marked by an arrow (in the left side of the figure) 

 is well demonstrated. None of the afferent visual fibers reaches the nonstriate 

 cortex. In this experiment a "boundary bundle,''' the most dorsal of the visual 

 radiation originating in tlie internal segment of tlie external geniculate body 

 (fig. 51) and forming the dorsal horizontal branch of the radiation, degenerated 

 supplying the most dorsal strip of the entire striate area, the latter imagined 

 stretched in a sagittal perpendicular plane. (Compare with figs. 2, 22, and 23.) 

 This figure shows also the mode of turning of the external sagittal stratum 

 around tlie dorsal edge of the tapetum. 



