434 journal of Comparative Neurology and Psychology. 



(epistriatum) by which again the dorso-lateral wall was more pushed 

 in a ventro-lateral direction. 



That really the large epistriatum is an important factor for the 

 eversion of the dorso-lateral forebrain wall is clearly proved by 

 the Teleosts, where the epistriatum on an average is larger than 

 in the Ganoids, and consequently the eversion of the palaeo- 

 pallium is also more striking, The same is seen in one of the 

 bony Ganoids, Amia calva, where the epistriatum is larger in the 

 middle of the forebrain, where consequently the eversion of the 

 latero-dorsal brain wall is also more strikms;- than in the frontal 



Fig. 2. 



Fig. I. Frontal section through the posterior part of the forebrain of Galeus canis. 

 Fig. 2. Frontal section through the anterior part of the forebrain of Amia calva. 



Fig. 3. Fig. 4. 



Fig. 3. Frontal section through the medulla oblongata of Galeus canis. 

 Fig. 4. Frontal section through the medulla oblongata of Hexanchus griseus. 



or caudal parts of the fore-brain. These differences and homolo- 

 gies were proved by an exact study of the course of the afferent 

 forebrain tracts, which (namely, the tr. taeniae) proved that this 

 interpretation was right. 



Nearly the same ideas about the different forms of forebrain 

 have been published by Studnicka, who however gave only 

 morphological proofs for this conception and whose interpreta- 

 tions were not generally, or rather were generally not, accepted, 

 probably because the conception of a palaeo-pallium was never 



^ Chimasra monstrosa has a forebrain of which the morphology shows both forms of development, 

 as in the frontal part of the forebrain the palaeo-pallium is large and inverted, whereas in the posterior 

 part of it, it is everted and reduced. 



