FOREBRAIN MORPHOLOGY 431 
epistriatum—a conception which does not coincide with the fact 
that this epistriatum is situated morphologically ventral to his 
striatum. Sheldon is of the opinion that the three parts are: 
a medial primordium hippocampi, a lateral nucleus olfactorius 
lateralis with a pyriform lobe, and a centrally situated palaeostria- 
tum. This opinion is contradicted by the fact that his primor- 
dium hippocampi is morphologically ventral to his nucleus olfac- 
torius lateralis and to his pyriform lobe. 
In my paper on the forebrain and ’tweenbrain of teleosts I have 
adopted another terminology. The primordium hippocampi of 
Johnston I have named ‘primordium pallii.’? Now I will change 
this name to ‘pallium’ only, as being more consistent with the 
conditions in lower vertebrates. This pallium corresponds fully 
with the pallium in inverted and evaginated brains as being a 
part of the brain situated dorsal to the zona limitans and the sulcus 
limitans externus. This pallium is subdivided into three parts, 
corresponding to the parts named by Kappers in another way. I 
have called them, respectively, the primordium hippocampi, 
the general pallium, and the pyriform lobe, and this nomenclature 
seems to me to be a consequence of my idea of the pallium in 
teleosts. In inverted brains the most dorsal (=medial) part of 
the pallium is the hippocampal pallium, the middle ( =dorsolat- 
eral) part the general pallium, and the ventral (=lateral) part 
the lobus pyriformis. Under the supposition that the subdivision 
of the pallium is the same in all lower vertebrates, the homology 
must be well settled. This supposition is no arbitrary one, but 
is supported by the fact that it is present already in selachians and 
Polypterus, that is, in more primitive forms than ganoids and 
teleosts. Thus, I think, there is no serious objection to make 
against the homology of the pallial parts. It is clear, however, 
that the homology is not perfectly proved until it is shown that 
the fiber connections do not speak decidedly against the homology. 
But it is still too early to draw the fiber connections into the 
discussion, these being too little known in selachians and holo- 
cephalians and practically unknown in Dipnoi and Polypterus. 
But so far as known to-day, the fiber connections do not speak 
against the homology. 
