1861.] BRAIN OF ATELES PANISCUS. 259 



which latter the corpus geniculatum hiternum looks almost like a 

 ganglion. 



The pons is large and convex, but nevertheless leaves tolerably 

 well-deKned corpora trapezoidea upon the surface of the sides of the 

 medulla oblongata, which last exhibits distinct oval olivary bodies. 

 The pituitary body, very large and spheroidal, is connected with a 

 prominent infundibulum, which is separated by a slight transverse 

 notch from the single corpus mammilfare. 



The commissures, third ventricle, pineal gland, &c., presented 

 nothing remarkable. The nerves are large in proportion to the 

 brain, particularly the olfactory nerves (which are very broad and 

 flat), the optic nerves, and the oculo-raotor nerves ; but beyond their 

 large size, they differ in no striking respect from the correspond- 

 ing parts in Man. 



EXPLANATION OF PLATE XXIX. 



(All the figures are of the natural size.) 



Fig. 1. Brain of Ateks paniscus (,female), almost fresh, viewed from above. 



Fig. 2. Bvain of a male Ateles, preserved in spirit and altered in form. 



Fig. 3. Under view of the female brain. The cerebellum has faUen back 

 by it3 own weight beyond the posterior edges of the cerebral 

 hemispheres, fl. flocculus. 



Fig. 4. Side view of fig. 1. 



Fig. 5. The same brain dissected, to show the lateral ventricles and their 

 cornua. e a, anterior; c d, descending; c p, posterior cornu; 

 * hippocampus minor. On the right side, the distance between 

 the extremities of the diverging lines indicates the whole length 

 of the cornu on one side, in the female brain. 



Fig. 6. The cerebellum viewed from above ; v s, vermis superior. 



Fig. 7. The cerebellum viewed from below ; v i, vermis inferior. 



Nomenclature and Lettering of all the Figures. 

 Cerebrum : 



Lobes: frontal lobe, Fr; parietal. Pa ; median, A/; temporal, Te; occi- 

 pital, Oca. 



Gyri (of the outer face) : 



1. Infero-frontal (etage surcilier). 



2. Medio-frontal (etage frontal moyen). 



3. Supero-frontal (etage frontal superieur). 

 1'. Supra-orbital (plis orbitaires). 



4. Antero-parietal (premier pli ascendant). 



5. Postero-parietal (deuxieme pli ascendant). 



5'. Postero-parietal lobule (lobule du deuxieme pli ascendant). 



6. Angular (pli courbe). 



7. Antero-temporal (pli temporal superieur). 



8. Medio-temporal (pli temporal moyen). 



9. Postero-temporal (pli temporal inferieur). 



10. Super-occipital (pli occipital superieur). 



11. Medio-occipital (pli occipital moyen). 



12. Infero-occipital (pli occipital inferieur). 



13. First external annectent "j 



14. Second external annectent / ,. , . x 



15. Third external annectent f" ^P^'^ ^^ P^^^'^S^ exterues). 



16. Fourth external annectent I 



