130 



VISION 



1 mm 



Figure 5 Transverse sections through (A) rostral and (B) midmesencephalic levels of 

 Mustelus canis. al, anterior lobe of cerebellum; bon, basal optic nucleus; cz, central tectal 

 zone; fr, fasciculus retroflexus; ic, intercollicular nucleus; il, inferior lobe of hypo- 

 thalamus; ip, interpeduncular nucleus; ni, nucleus interstitialis; np, nucleus profundus 

 mesencephali; nlll, oculomotor nucleus; pz, periventricular tectal zone; sz, superficial 

 tectal zone; ts, torus semicircularis; vt, ventral thalamus; III, oculomotor nerve. 



