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MANUAL OF PHYSIOLOGY. 



The primitive cerebral hemispheres first appear as two lobes 

 growing out from the front of the anterior part of the first cerebral 



Chick on the third day, seen from beneath as a transparent object, the 

 head being turned to one side. (Foster and Balfonr.) a'. False amnion. 

 a. Amnion. CH. Cerebral hemisphere. F.B., M.B., H.B. Anterior, Mid- 

 dle, and Posterior cerebral vesicles, op. Optic vesicle, ot. Auditory vesi- 

 cle, ofv. Omphalo-mesenteric veins. Ht. Heart. Ao. Bulbus arteriosus. 

 Ch. Notochord. Of.a. Omphalo-mesenteric arteries. Pv. Protovertebrse. 

 x Point of divergence of the splanchnopleural folds, y. Termination of the 

 fore-gut, V. 



vesicle. The floor of these lobes thickens to give rise to the cor- 

 pora striata, and the roof develops into the hemispheres proper. 



