434 
NILS HOLMGREN 
INVERTED FOREBRAIN 
EVERTED FOREBRAIN 
Lateral part of the everted 
1 | Hippocampal pallium 
pallium 
Pallial 2 | General pallium Dorsal part of the everted 
parts pallium 
3 | Pyriform pallium with Medial part of the everted 
hypopallium pallium 
Absent (generally) 
Zona limitans lateralis 
Zona limitans medialis 
Sulcus limitans pallii (some- 
times present) 
Zona limitans 
Absent 
7 | Sulcus limitans externus Sulcus limitans externus 
8 | Sulcus limitans medialis Absent 
9 | Nucleus olfactorius lateralis Nucleus olfactorius lateralis 
10 | Tuberculum olfactorium Nucleus precommissuralis pars 
Sub- superior 
pallial 411 | Nucleus taeniae Nucleus entopeduncularis 
parts taeniae 
12 | Nucleus lateralis septi Nucleus precommissuralis pars 
inferior 
13 | Nucleus medialis septi Nucl. olfactorius anterior pars 
| precommissuralis 
THE EVOLUTION OF THE FOREBRAIN IN THE LIGHT OF 
VERTEBRATE PHYLOGENY 
The evolution of the forebrain in vertebrates is a problem which 
cannot be solved by the comparative anatomy of the brains of 
now living animals only, as those represent only the upper 
terminal branches of the great vertebrate stem. Certainly, how- 
ever, every worker in comparative neurology has formed for 
himself an idea about this problem, which coincides with his 
idea about brain morphology. Very few, however, have tried to 
examine to what degree their opinions answer to the vertebrate 
phylogeny, established on the palaeontological results or on char- 
acters taken from other organic systems. It is clear that a phy- 
logeny of the forebrain, if a well-grounded one, must on the whole 
correspond with the phylogeny established on the anatomy of 
other organs. ; 
