FOREBRAIN MORPHOLOGY 413 
This above-quoted view of Edinger coincides by no means 
with the fact that the forebrain in embryonic selachians contains 
the main part of structures characteristic of higher vertebrates. 
Edinger’s view thus is morphologically false, based as it is on a 
false interpretation of the selachian forebrain. Physiologically, 
Edinger’s view perhaps may be right; but the principal reason 
for his view, the special connections of the ‘episphaerium’ in sela- 
chians, is not established by real observations; on the contrary, 
there are olfactory fibers of the second order present entering the 
‘episphaerium.’ 
Through the results of my observations on Acanthias, the 
opinion of Lundahl (v. Vetakad:s Handl., Bd. 59. No. 2, 1918), 
expressed in the most categorical manner, concerning the forebrain 
phylogeny has no real reason. Lundahl interprets the part of the 
brain dorsal to the zonae limitantes as a ‘palaeopallium.’ This 
view he bases on the suggestion that this part of the forebrain is 
built up by ‘‘numerous, little differentiated nerve-cells,” diffusely 
arranged without forming typical layers. And he finds the state- 
ment of this description in papers of v. Kuppfer, Kappers, C. L. 
Herrick, Edinger, Jakob, and Johnston. That Lundahl’s opinion 
of the pallium in selachians is false follows immediately from the 
above description of the embryological development of the pallium 
in Acanthias. 
This development also shows the extreme error of the interpre- 
tation of the phylogenetic development of the different cortices 
in the reptilian brain as given by different authors, according to 
whom the ‘palaeopallium,’ the ‘archipallium,’ and the ‘neopallium’ 
develop successively from a ‘matrix’ situated at the fissura rhin- 
alis externa. Such a matrix does not exist in the ontogenetic 
development. The cortices develop simply from the underlying 
part of the neuroblastic layer and there are no signs present of a 
successive displacing of cortical units from a place of origin at the 
‘fissura rhinalis externa’ to more medial situation. All that is 
true in such a description is that the cortices are developed suc- 
cessively, the pyriform cortex being developed a little before the 
general pallial cortex; but it is false that all cortices are derivatives 
from a common matrix, situated as said before. The hippo- 
