68 Journal of Comparative Neurology. 



clined to think that it was this body to which Mayer gave the 

 name of "Hirnrinde," and so treated jt in a paper read before 

 the Baltimore meeting of the American Society of Morpholo- 

 gists ('oi b). It seems to me now that it is the dorsal portion 

 of the lateral expansion which Mayer considers to be the cor- 

 tex. If so. he has wholly disregarded the epistriatum ! My 

 mistake in understanding Mayer's description was due to the 

 fact that it did not seem possible for anyone to overlook so 

 large and conspicuous a body with so characteristic a structure 

 as the epistriatum. Moreover, the cells of the epistriatum 

 might be called pyramidal cells, while none in the dorsal part 

 of the lateral expansion have any resemblance to pyramidal 

 cells. This latter fact, together with the relations of the fiber 

 tracts to and from this part of the fore brain show that it is not 

 at all a cortex, but merely the area olfactori^. Since this is 

 Mayer's own description of this center, he has precluded the 

 possibility of applying to it the name cortex. The use of such 

 terms as olfacto-corticalis, cortico-habenularis, etc., are there- 

 fore inadmissable. 



Certain other statements made by this author deserve some- 

 what more detailed examination. He includes certain giant 

 cells, which give rise to MOllerian fibers, in the grey matter 

 of the "corpora quadrigemina" for no apparent reason. The 

 cells lie in the central grey of the lateral and ventral wall of 

 the mid brain. He states that the greater part of the posterior 

 commissure is formed of fibers from the tectum destined to 

 constitute the fasciculus longitudinalis posterior. In fact very 

 few fibers from the tectum enter the posterior commissure, and 

 the suggestion that the fasciculus is formed of fibers from either 

 the tectum or posterior commissure can not be entertained for 

 a moment, in the light of the origin of this fasciculus in other 

 vertebrates from cells in the thalamus and from motor cells situ- 

 ated along the route of the fasciculus in the base of the brain. 

 The fibers from the epiphysis to the posterior commissure can 

 not exist in Lampetra and must be regarded as very doubtful 

 from the fact that in known cases the fibers from the epiphysis 

 enter the ganglia habenulae. The curious suggestion that- 



