112 PL ATT. 



DESCRIPTION OF PLATE VI. 



Sec. 9. Horizontal section through the primary trochlearis. 



Sec. 10. Horizontal section through the mandibular cavity, showing the anterior 

 prolongation of this cavity, from which the superior oblique eye-muscle is formed, 

 and also showing the beginning of the rudimentary muscle (mus. e.). 



Sec. 11. The fibrous root of the permanent trochlearis. 



Sec. 12. Cross-section through the root of the " thalamic " nerve. 



Sec. 13. Median portion of the permanent trochlearis at the stage represented in 

 sec. 7. 



