RECONSTRUCTION OF xMYCETES SENICULUS 



=37 



formation seems to be continuous with the matrix of gray matter from which 

 develop the zona incerta of the diencephalon and also that of the less differ- 

 entiated hypencephalic gray matter. 



FIG. 130. DORSAL SURFACE OF THE GRAY MATTER OF THE BRAIN STEM, 



MYCETES SENICULUS. 

 Key to Diagr-\m. inf. coll., Inferior Colliculus; nucl. ofburdach, Nucleus of Burdach; nucl. of deiters. 

 Nucleus of Deiters; nucl. of coll, Nucleus of GoII; ret. form., Reticular Formation; subst. gel. rolando. 

 Substantia Gelatinosa of Rolando; sup. colliculus, Superior Colliculus; vent, coch.. Ventral Cochlear 

 Nucleus. 



The Pontile Nuclei 



In reconstruction the pontile nuclei appear rather abruptly at the level 

 of the trapezoid body. The nucleus is considerably more massive than in the 

 Lemur mongoz and the Callithrix jacchus, and is tunnelled on both sides by 

 the descending pyramidal and pallio-pontile tracts. This again produces the 

 typical arrangeiiient of a lateral and mesial buttress, connected ventrally 

 and dorsally by the superficial and the deep layer of the pontile nucleus. The 

 simple arrangement of the nucleus as found in the Lemur mongoz and the 

 marmoset now becomes somewhat more complicated w ith masses of nuclear 



