194 



ZOOLOGY 



SECT. 



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

 are roofed over by a conical, tent-like cJioroid plexus (ch. plx. 1). 

 The cavities of the small, spindle-shaped hemispheres (crl. A.) com- 

 municate with the third ventricle by wide foramina of Monro 



Q 



ccL.obl 



FIG. 851. Callorhynchus antarcticus. A, dorsal view of brain after removal of the mem- 

 branes ; B, side view with the membranes in place, cblin. cerebellum ; ch. plx. 1, choroid 

 plexus of fore-brain, and ch. plx. 2, of hind-brain ; cp. rst. corpus restiforme ; cp. str. corpus 

 striatum ; crb. h. cerebral hemisphere ; di. coe. diacoele ; dien. diencephalon ; for. M. foramen 

 of Monro ; lb. inf. lobus inferior; med. obi. medulla oblongata ; mt. me. metaccele ; Nr. 3, optic 

 nerve ; Nv. 5, trigeminal ; Nv. 8, auditory ; Nv. 10, vagus ; olf. 1. olfactory bulb ; olf. p. 

 olfactory peduncle ; opt. 1. optic lobe ; pn. b. pineal body ; pn. s. pineal stalk ; ply. pituitary 

 body. 



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

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

 tube, the olfactory peduncle (olf. p.), bearing at its extremity a 

 compressed olfactory bulb (olf. /.). 



