Sargent. — Optic Reflex Apparatus. 



TLATE 11. 



Fig. 71. Raja erinacea, 14 cm. long. Diagrammatic sagittal section of the mid- 

 brain, showing the ' Dachkern ' and the fihre-tracts arising from it, and 

 the metliod of formation of Reissner's fibre. 



Fig. 72. Amia calva, advanced larval stage. Sagittal section of the midbrain, 

 somewhat diagrammatic, showing the mode of formation of Reissner's 

 fibre. 



