392 



DAVIDSON BLACK 



Fig. 7 Rana catesbeana. Transverse section through the brain stem at the 

 level of the trochlear nucleus. Abbreviations: Aq.c., iter; Nu.IV., trochlear 

 nucleus; Vent, op., optocoele. Other abbreviations as before. 



Fig. 8 Rana catesbeana. Transverse section through the brain stem at the 

 level of the oculomotor root exit. Abbreviations: Com.aiis., ventral tegmental 

 commissure; N .III., oculomotor root; Nu.IIL, medial and lateral moieties of the 

 oculomotor nucleus. Other abbreviations as before. 



