GENERAL CONSIDERATIONS. 



41 



Reference letters. 



ans anaate. 



b buttress. 



cal callosum. 



calc calcar. 



cf coufinis. 



cl callosal fissure. 



col.. .- -.collateral. 



cor coronal. 



or cruciate. 



el ectolateral. 



f fimbria. 



g genual. 



hip hippocampus. 



1 lateral. 



marg marginal. 



me medicomu. 



ml medilateral. 



pc postcornu. 



per postcruciate. 



pi plexus. 



pre _. precornu. 



prcr precruciate. 



prh postrhinal. 



prsp presplenial. 



prgs presupersylvian. 



psp postsplenial. 



pss postsupersylvian. 



r rostral. 



rh rhinal. 



so superorbital. 



sp splenial. 



str striatum. 



Syl Sylvian. 



S8 supersylvian. 



th thalamus. 



ur ursine lozonge. 



EXPLANATION OF PLATE V. 



Fig. 1. The ventral aspect of the brain of the fur seal, Callorhinus ursiniis, showing in addition to the 

 fissures the cranial nerves and the cerebellum. On each side of the latter is a depression 

 into which fits the petrosal portion of the temporal bone. 



2. The dorsal aspect of the brain, showing the cerebellum largely concealed by the cerebrum. 



3. The left lataral aspect of the cerebrum. 



4. The right lateral aspect of the cerebrum. 



5. The mesal .aspect of the right hemicerebrum. 



6. The mesal aspect of the left hemicerebrum. 



EXPLANATION OF PLATE VI. 



Fig. 1. The ventral aspect of the brain of the hair seal, Fhoca vitidina, slightly modified from Tiede- 

 maun's figure. 

 2 The dorsal aspect of the cerebrum of Phoca vituUna, after Tiedemann. 



3. The left lateral aspect of the cerebrum. 



4. The right lateral aspect of the cerebrum. 



5. The mesal aspect of the right hemicerebrum. 



6. The mesal aspect of the left hemicerebrum. 



EXPLANATION OF PLATE VII. 



Fig. 1. The left lateral aspect of the cerebrum of the sea lion, Zalophus calif or nianua. 



2. The right lateral aspect of the cerebrum of Zalopliua. 



3. The mesal aspect of the right hemicerebrum. 



4. The mesal aspect of the left hemicerebrum. 



5. The left lateral aspect of the cerebrum of Ursus thibetianus. 



6. The mesal aspect of the right hemicerebrum of Ursus. 



7. Dissection of the left hemicerebrum of Callorhinus, showing the lateral ventricle with a very 



rudimentary postcornu. 



8. Dissection of the left hemicerebrum of Phoca vitulina, showing the presence of the calcar and 



large postcornu in the lateral ventricle. 



