Nuclei Tuberis Laterales and the Ganglion Opticum Basale. 37 



just what criteria have been employed in setting aside each cell group: and 

 moreover we should carefully distinguish between such cell groups of 

 different authors as are identical and such as do not entirely correspond. 



Taking up the various cell groups of the hypothalamus, Friedemann des- 

 cribes the nucleus intercalatus corporis mammillaris and the nucleus 

 paraventricularis just as I had found them in man, and he adopts my names 

 for them. He also adopts my name "nucleus mammillo-infundibularis "; 

 I have previously in this article pointed out that this name must be 

 changed, and have adopted instead that of nucleus " tubero-mammillaris." 

 But it is not clear to me that Friedemann has included all the cells in this 

 group which I have assigned to it; unfortunately the illustrations (photo- 

 graphs) are of little value in showing the distribution of each cell type. 

 It is certain that his nucleus posterior pedamenti lateralis (Fig. 9, Pip) 

 is a portion of my nucleus tubero-mammillaris; moreover Friedemann 

 has called attention to the fact (p. 367) that his lamina grisea separans 

 (Fig. 9, Igs) is a portion of this same nucleus. Such subdivisions are of 

 course desirable for their topographical value, but the common cell charac- 

 ter should be kept in mind. In considering the basal optic ganglion Friede- 

 mann has fallen into the same error that I did in my monograph on the 

 diencephalon, and for the same reason, since both of us were not primarily 

 interested in the telencephalon; this error consists in considering merely 

 the cell mass which follows the oro-lateral border of the optic tract as 

 constituting this ganglion. It is certain that to the basal optic ganglion of 

 cercopithecus must be added Friedemann's " nucleus anterior pedamenti 

 lateralis " (p. 370 and Fig. 11, Pla) as well as his " stratum supraopticum " 

 (p. 369 and Fig. 9, Sso.). That these two cell groups belong to the basal 

 optic ganglion is clear both from the descriptions and illustrations. It is 

 unfortunate that neither the cross sections nor the horizontal sections 

 illustrated give the region just caudal to the optic chiasm. Friedemann's 

 cross sections may be best compared with my Series D of man (Figs. 11 to 

 18) since the plane of section is similar: in comparing these two series it is 

 evident that the most oral section (Fig. 11) of Friedemann stops short 

 of a most important region of the basal optic ganglion. Again his first 

 horizontal section (Fig. 12) likewise fails to give this region near the optic 

 chiasm. (The omission of this region is only natural, since Friedemann's 

 article deals primarily with the diencephalon.) Accordingly I see no reason 

 to believe that the basal optic ganglion in cercopithecus is essentially 

 different from that in other animals from man to the marsupials. 



In Friedemann's description of cercopithecus I am unable to find any 

 cell groups which would correspond to the nuclei tuberis laterales, 

 and unfortunately the illustrations are of such a nature (photographs) as 

 not to reveal the presence of such groups. It is not probable that the nuclei 

 tuberis laterales are wanting in cercopithecus, since they are present in 

 macacus and are indicated even in the lemur; their presence, if indeed they 

 occur in cercopithecus, might easily be overlooked unless one had seen 

 them in man, where these nests of cells are very definite. The fact, which 



