496 C. JUDSON HEKKICK 



primitive and in all vertebrates receives olfactory fibers directly 

 by way of the lateral olfactory tract. Nevertheless I have shown 

 that from the first appearance of the hemisphere the primordium 

 from which the pyriform lobe developes is clearly separate from 

 that of the sub-pallial parts, and it is generally recognized as 

 showing in mammals some cortical differentiation. 



It is difficult to frame any general scheme of anatomical sub- 

 division of the telencephalon which will be readily applicable to 

 all aberrant types, e.g., to the teleosts, where the concentration 

 of all massive tissues in the floor of the ventricle and its subse- 

 quent eversion has confused the arrangement of the primary 

 laminae. The above table, like that of the BNA upon which it 

 is based, is drawn up with particular reference to the mammals, 

 whose telencephalon is largely evaginated into tfie hemispheres. 

 A subdivision based on phylogeny may be suggested as follows: 

 Telencephalon 



Ventriculus impar telencephali 

 Ventriculus lateralis 

 Pars ventralis 



Chiasma opticum 

 Commissura postoptica 

 Commissura anterior 

 Lamina terminalis 

 Pars ventro-medialis 

 Nucleus preopticus 

 Corpus precommissurale 

 Tuberculin) 1 olf actorium 

 Pars ventro-lateralis 

 Corpus striatum 

 Pars dorsalis s. pallialis 



Tela chorioidea telencephali 

 Paraphysis 

 Plexus lateralis 

 Pars dorso-medialis 

 Cortex medialis 



Cortex hippocampi 

 Fascia dentata 



