188 



ZOOLOGY 



SECT. 



distinct prosencephalon, which gives off the cerebral hemispheres 

 (crb. h.) right and left. The combined diaccele and prosoccele 

 (di. COB.) are widely open above in a brain from which the mem- 

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

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

 cavities of the small, spindle-shaped hemispheres (crb. h.), some- 



olf.l 



rn.ed.obl 



FIG. 862. Callorhynchus antarcticus. A, dorsal view of brain after removal of the 

 membranes ; B, side view with the membranes in place, cblm. 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. diaccele ; dien. diencephalon 

 for. M. foramen of Monro : Ib. inf. lobus inferior ; med. obi. medulla oblongata ; int. coe 

 metaccele ; Nv. 2, optic nerve ; Nv. 5, trigeminal ; Nv. 8, auditory ; Nv. 10, vagus ; olf. I 

 olfactory bulb ; olf. p. olfactory peduncle ; opt. 1. optic lobe ; pn. b. pineal body ; pn. s 

 pineal stalk ; ply. pituitary body. 



times regarded as corresponding to olfactory lobes only, communicate 

 with the third ventricle by wide foramina of Monro (for. M.), 

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



