FIG. 207. Scyllium catulus. Dissection of the brain and of some of the cranial 

 nerves. A. Ventral view. B. Dorsal view. C. Longitudinal median 

 section. D. Diagram of embryonic brain showing the three primary 



vesicles. 



1. Cerebrum. 2. Pineal stalk. 3. Olfactory lobe. 4. Cerebral hemi- 

 sphere. 5. Thalamencephalon. 6. Pituitary body. 7. Optic lobes. 

 8. Optic lobes. ^ 9. Cerebellum. 10. Boof of the hind-brain. 



11. Superior oblique muscle. 12. Internal rectus muscle. 13. Superior 

 rectus muscle. 14. External rectus muscle. 15. Ninth or 



glossopharyngeal nerve. 16. Branch of vagus nerve to second 



branchial cleft. 16 a. Branch of vagus nerve to third branchial 



cleft. 17. Main trunk of vagus to fourth and fifth gill-slits, to lateral 



line and to viscera. n. Optic nerve. n a. In A, optic chiasma. 



rv, v, vi, vn, vin, ix and x. Boots of fourth to tenth cranial nerves. In 

 D, i, n, in represent the first, second and third primary vesicles of the 

 embryonic brain. 



