MOTOR NUCLEI IN PHYLOGENY 491 
Oculomotor and trochlearis nuclei and roots (Nu. et. rad. Nn. IIT 
& IV). The trochlear and oculomotor nuclei in Selache maxima 
have already been described and charted by Huet (47) and dis- 
cussed by Kappers (66). However, a short description of these 
nuclei and their roots will be given here for the sake of com- 
pleteness. 
Tectum 
aX 
MYYANu.V.m. 
‘ 4 
Figs. 14, 15 and 16 Selache maxima. Outlines of transverse sections to 
illustrate the topography of the medulla. Abbreviations: N.III., oculomotor 
roots; N.JV., trochlear nerve; Nu.mag.tect., nucleus magnocellularis tecti; 
Nu.III., oculomotor nucleus; Nu.IV., trochlear nucleus; Nu.V.m., motor tri- 
geminus nucleus. Other abbreviations as in figures 10 to 12. 
