THE SYSTEMATIC ANATOMY OF A FCETAL SEA-LEOPARD. 



249 



Fig. 2. Dissection of the Sea-Leopard Seal, to show the principal viscera in situ (ventral aspect): — 



1. Thyroid and lowest parathyroid. 



2. Trachea. 



3. Thymus. 



4. Left lung (upper lobe). 



5. Left auricular appendix. 

 5a. Left lung (lower lobe). 



6. Ventricular portion of heart. 



7. Diaphragm. 



8. Left lobe of liver. 



9. Umbilical cord. 



10. Patent allantoic duct. 



11. Urinary bladder. 



12. Coils of small intestine. 



13. Umbilical vein. 



14. Eight lobe of liver. 



15. Gall bladder. 



15a. Right lung (middle lobe). 



16. Right auricular appendix. 



17. Right lung (upper lobe). 



18. Arch of aorta. 



Plate XX. 



Anatomical details of the brain and cranial and nasal fossae. 



Fig. 1. The brain from the dorsal aspect : — 



1. 4th ventricle (floor). 



2. Lamellae of cerebellar hemisphere. 



Fig. 2. The brain from the side : — 



1. Olfactory lobe. 



2. Fissure of Sylvius. 



3. Infundibulum. 



4. 3rd nerve. 



3. Superior surface of cerebral hemisphere. 



4. Crura cerebri. 



5. Medulla oblongata. 



6. Cerebellum. 



7. Cerebral hemisphere. 



Fig. 3. Mesial surface of a median sagittal section of head :- 



1. Lower jaw. 



2. Tongue. 



2 1 . Lamina terminalis. 



3. Hypophysis cerebri. 



4. Medulla oblongata. 



5. 4th ventricle. 



6. Cerebellum. 



7. Corpora quadrigemina. 



8. Optic thalamus. 



9. Falx cerebri. 



9 1 . Corpus callosum. 



10. Nasal fossa (lower). 



11. Nasal septum. 



12. Buccal cavity. 



Fig. 4. Nearly mesial sagittal section of brain to show distribution of grey and white matter, and general 



relations of parts : — 



1. Nuclei of vagus and hypoglossal nerves. 



2. Grey matter of cerebellar hemisphere. 



3. Pia mater. 



4. Grey matter of cortex cerebri. 



5. Superficial white matter of cortex. 



6. Grey matter lining cavity of prosen- 



cephalon, just showing. 



7. Portion of choroid plexus. 



8. Portion of 3rd ventricle in infundibulum. 



9. Grey matter in optic thalamus. 



ii. Part of prosencephalon communicating with 



lateral ventricle, 

 iv. 4th ventricle. 



Fig. 5. Mesial surface of sagittal section of head, the nasal septum and falx having been removed 



t. Tongue. 



hy. Hypophysis. 



m.o. Medulla oblongata. 



cb. Cerebellum. 



p. Pons. 



TRANS. ROY. SOC. EDIN., VOL. L. PART I. (NO. 8). 



op. Optic thalamus. 



h. Cerebral hemisphere. 



olf.l. Olfactory lobe. 



eth.t. Ethmo-turbinal bone. 



mx.t. Maxillo-turbinal bone. 



35 



