238 RALPH EDWARD SHELDON 
relation different parts of the nervous system, and in causing it to 
react as one correlated, organic whole. 
6. THE MORPHOLOGICAL AREAS OF THE FOREBRAIN 
On the basis of the facts brought forward in the previous 
discussion, the forebrain of teleosts may be divided into morpho- 
logically distinct centers, according to the following table: 
Telencephalon. 
Bulbus olfactorius 
Nucleus olfactorius anterior 
Pars lateralis hemisphaerii (pars dorso-lateralis, Herrick) 
Nucleus olfactorius lateralis 
Tuberculum anterius 
Tuberculum laterale 
Lobus pyriformis 
Nucleus teniae 
Pars medialis hemisphaerii (pars ventro-medialis, Herrick) 
Corpus precommissurale 
Nucleus medianus 
Pars commissuralis 
Pars supracommissuralis 
(Nucleus intermedius, in part, at least) 
Primordium hippocampi, or nipelene olfactorius dorsalis (pars dorso-medi- 
alis, Herrick) 
Palaeostriatum (pars ventro-lateralis, Herrick) 
Nucleus commissuralis lateralis 
Nucleus entopeduncularis 
Nucleus preopticus 
Pars parvocellularis 
Pars magnocellularis 
Johnston (711) has made an important contribution to the mor- 
phology of the forebrain of fishes in his analysis of the ‘somatic 
area’ of selachians. This paper came into my hands after the 
present contribution was ready for the press, and I have not had 
an opportunity to make a thorough inquiry into the teleostean 
homologies of this selachian area. Pending further study of 
this question, I may say that it now seems probable that some 
or all of the following regions of the carp brain correspond with 
the selachian somatic area of Johnston: palaeostriatum, nucleus 
teniae, nucleus intermedius of the precommissural body, nucleus 
