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H. K. HARTLINE, F. RATLIFF AND W. H. MILLER 







/:■ 





Fig. 5. Electron micrographs of eccentric cell axon {E), branch (B), and neuro- 

 pile (TV). The inset is low magnification; in the higher magnification micrograph 

 of the same region (remainder of figure), showing part of the branch and neuro- 

 pile, small dense circular outlines (synaptic vesicles) are seen. The significance of 

 the difference in size of the vesicles is unknown. 



Fig. 6. Inhibition of the activity of an ommatidium in the eye ofLimulus produced 



by illumination of a nearby retinal region. Oscillogram of action potentials 



in a single optic nerve fiber. See text for description. Time in I sec. (From 



Hartline et ah, 1953). 



