158 Journal of Comparative Neurology. 



what larger than the latter, and the dark protoplasm mass 

 surrounding the round nucleus of these cells is more highly 

 developed. It is possible to trace the processes of these cells 

 into the fibres of the radial system. In the fibrous zone 

 round cells are scattered, as well as rod-like cells of the 

 neuroglia. 



" In the ventral portion of the cleft-like canal connecting 

 the lobus infundibuli with the mesencephalic ventricle a 

 ganglionic body composed of large cells occupies either side. 

 Out of these ganglia springs a tract of non-medullated fibres 

 which, passing caudad, subdivides, part of the fibres passing 

 to the caudal part of the lobus infundibuli, and part to the 

 dorsal portion of the sacculus vasculosus. Associated with 

 this system is a rather large bundle of non-medullated fibres 

 derived from a small cluster of nerve cells lying dorsad to 

 the above-mentioned ganglion and ventrad to Meynert's 

 bundle, immediately beneath the epithelium. The ventral 

 portion of the caudal wall of the lobus passes into the thin 

 epithelial wall of the saccus vasculosus, a part of the fibrous 

 layer entering it. The saccus itself is a broad, very vascular, 

 folded sac, clothed within by a peculiarly modified epithe- 

 lium. 



"The discoidal hypophysis consists of two completely 

 distinct parts. The caudal portion is composed of three or 

 four lobes, into each of which passes a thick bundle of non- 

 medvdlated fibres, which pass to the ventral portion and sub- 

 divide in the several sacculi. The sacculi of the cephalic 

 portion are covered, like the former, with multilamellate epi- 

 thelium with fusiform cells, but no nerve fibres are present. 

 The interstitial substance is connective tissue only. A thin 

 layer of epithelium connects the two portions. 



" The ganglion habenulce. — Cephalad to the ganglion inter- 

 pedunculare and ventrad to the transverse fibres of the com- 

 missura ansulatse, there are two longitudinal bundles, which 

 could be followed caudad only to the interpeduncular ganglia. 

 These are Meynert's bundles, the right being much stronger 



