526 Journal of Comparative Neurology and Psychology'. 



olfactorius and gives rise to some fibers of the tractus olfacto- 

 habenularis. Considerations of practical convenience and clearness 

 would dictate that this secondary olfactory center be included in the 

 telencephalon, not in the diencephalon. 



Edinger distinguishes a neencephalon from a palgeencephalon. 

 His palseencephalon includes the lower segTaents of the brain together 

 with that portion of the telencephalon which he calls the hypo- 

 sphserium. The neencephalon is the same as his epispha^rium and 

 includes the tertiary olfactory centers (Elliot Smith's archipallium) 

 and the general cortex (Grosshirn, Elliot Smith's neopallium). Is 

 it true that the whole of the lower segments of the brain are to be 

 set in contrast to that part of the telencephalon to which the name 

 episphserium is given ? Are the centers for the cochlear nerve in the 

 medulla oblongata, the inferior olives, the nucleus dentatus in the 

 cerebellum and the auditory centers in the inferior colliculus and 

 metathalamus older than the tertiaiy olfactory centers or the general 

 cortex ? Or is it true only that our knowledge of them is older ? 

 The terms palseencephalon and neencephalon are undoubtedly useful 

 as expressions of the functional evolution and growth in organiza- 

 tion of the whole brain ; but as descriptive terms for the topogi-aphical 

 features of the brain they would not be useful in the lower brain 

 segments and are decidedly misleading when applied to the forebrain 

 alone. 



The terms hyposph£erium and episph?erium seem to apply fairly 

 well in mammals, but I see no advantage in introducing new terms 

 which will not apply to the brains of lower vertebrates as well. 



In describing the minor divisions of the telencephalon Edinger is 

 neither consistent with himself nor with the majority of authors. 

 His description of the olfactory centers is quite confusing and con- 

 tains several self-contradictions. The Ixidy into which the olfactory 

 nerve enters he calls (1908, p. 252) the lobus olfactorius. Almost 

 all recent authors have agreed to use the name bulbus olfactorius for 

 this, while the term lobus olfactorius is given to the collection of 

 secondary centers which make up a greater or less part of the body 

 of the forebrain. To this posterior part Edinger proposes to give 

 the name lobus parolfactorius. This term replaces the term area 



