32 Edward F. Malone. 



reading it found no reason for modifying my conception of this region. 

 In tile second place some of tlie articles are concerned with animal forms 

 so far removed from those upon which I have worked that the recogni- 

 tion of homologous groups is by no means certain. Finally the 

 descriptions of cell groups are often so inadequate and so little attention 

 is given to the differences in cell type as to make the literature, except in 

 rare cases, almost unintelligible ; this is true especially in those articles 

 which are concerned with the brain of man and the higher mammals. 

 Accordingly the results of other workers on the cell groups of the hypo- 

 thalamus have not been incorporated to any great extent into the body of 

 this article, but are here appended for the sake of completeness ; to treat 

 the greater portion of the literature otherwise would render the subject 

 of this article needlessly obscure. The following consideration of the 

 literature is given for the benefit of those who wish to make a careful 

 study of the region in question ; accordingly it appears advisable not to 

 give an abstract of the various articles, since the complete accounts must 

 be read by those for whom the following consideration is intended. On 

 the contraiT I shall for the most part confine myself to a consideration 

 of certain points, showing wherein certain accounts are correct and 

 wherein erroneous, and wherein some descriptions are altogether unin- 

 telligible. 



The description of tlie cell groups of the hypothalamus contained in my 

 monograph on the human diencephalon has been referred to in numerous 

 places in the text and a further reference is unnecessary. 



In Strieker's Manual of Histology (American translation) Meynert 

 gives a brief but fairly clear description of the basal optic ganglion; on 

 p. 688 he says: "At the lateral border of the tuber cinereum lies the 

 inferior optic ganglion, which is 1.5 mm. broad, and contains spindle-shaped 

 cells 30 /x in length and 15 ii in breadth. It begins just above the optic 

 commissure and stretches along immediately over the tractus opticus as far 

 as the posterior border of the tuber cinereum, a distance of more than a 

 centimeter. I regard, with Luys, this optic ganglion as a part of the tuber 

 cinereum, because it projects downwards, in company with the latter, into 

 the lamina cinerea, beyond the surface of the lamina perforata anterior, of 

 which J. Wagner considers it to be a part, and because it extends farther 

 backward than the latter. Like the tractus itself, however, it certainly 

 follows the inner border of the anterior pert, space. On profile sections 

 (Fig. 270, IT) this ganglion has a sickle-like shape, the concavity looking 

 forward. According to Luys, the two ganglia touch at the median line, 

 a fact which I have not been able to verify, etc." From this description 

 and from a study of Fig. 268 it is clear that Meynert had in mind a cell 

 group which has much in common with that described under the same name 



