328 Dr. Macartney on the Structure of the Brain in the Chimpanzee, S^c. 



EXPLANATION OF THE PLATES. 



Plate I. — Fig. 1. Was drawn from an accurate plaster cast of the upper sur- 

 face of the brain of the Chimpanzee. 

 Fig. 2. Was taken from the cast of the lower surface of the same 

 brain. Both these figures are of the natural size. 



Plate II. Exhibits the different parts as they were found on the inferior sur- 

 face of the brain of an idiot. 

 a a. The two lateral lobes of the cerebellum, exceedingly small, 



and imperfectly formed. 

 h h. The membranous cells, which held a reddish fluid. 

 c. The pons or commissure of the cerebellum, also small and im- 

 perfect. 

 d d. The pyramidal bodies. 



e e. The olive-shaped bodies, making scarcely any projection. 

 ff. The olfactory nerves. 

 gg. The optic nerves. 

 , h h. The third pair of nerves. 

 The other nerves were not preserved. 



