1'I4 



ZOOLOGY 



SECT. 



membranes have been removed (^4), but in the entire organ (B) 

 are roofed over by a conical, tent-Hke choroid 2^ic^'-us {ch. pbx 1). 

 The cavities of the small, spindle-shaped hemispheres {crh. /i.) com- 

 municate with the third ventricle by wide foramina of Monro 



B 



ehlm 



cp rst- 



mt.coc 



chpL^t' \ °P\^ ' . 



crbTv / W " ' ^ ■ 



cLt€.n. Nvy. 

 lb vnf 



P^^ 



ntecL.obl 



Fir;. Sol. — Callorhynchus antarcticus. A, dorsal view of brain after removal of the mem- 

 branes ; i>, side view witli tlic uieuibraiies in ]ilace. clilm. cereliellum ; rk. fil.e. 1, eboroid 

 plexus of fore-brain, and eh. 'jilx. 2, of hind-brain ; cp. rsl. corpus restifornie ; cp. sir. corpus 

 .striatum ; crb. h. cerebral bemi.sphere ; di. roe. diacfele ; ilUn. diencephalon ; for. M. foramen 

 of Monro ; Ih. inf. lobus inferior; wed. ohi. medulla oblongata ; ml. roc nietaccele ; Nr. ;;', optic 

 nerve ; iW. .-7, tVigcuunal • A'v. <S', a\iditory ; A'c /'/, vagus ; olf. I. olfat^tory bulb ; olf- T>- 

 olfactorj' peduncle ; o/>(. /. optic lobe ; j)/». b. pineal body ; -pii. •«. pineal stalk ; jphi. )iituitary 

 body. 



(for.M), partly blocked up by hemispherical corpora striata {(p. str.). 

 Each hemisphere is continued in front into a delicate thin-walled 

 tube, the (ilfadory 2'>cd%ndc {olf. p.), bearing at its extremity a 

 compressed olfactory bulb (olf. I.). 



