i62 Journal of Comi'Arativk Neukolocjv. 



pouch of the diatelUi, such as may be detected in all reptiles 

 in which the epiphysis is strongly developed. The asym- 

 metry upon which Goronowitsch lays so much stress is slight, 

 and more apparent than real. The fact that it extends so far 

 cephalad between the hemispheres, is an incident to the 

 cephalad projection of the epiphysis. It may be useful to 

 first study the structure of the latter. 



The epiphysis springs from the most caudal portion of the 

 i-ecessus pinealis, which is clothed, as usual, with very large 

 and dense epithelium, very different from that of the adjacent 

 parts of the thhd ventricle. There seems to be a perforation 

 passing obliquely dorso-caudad, forming the communication 

 between the cavity of the epiphysis and the recessus. The 

 epiphysis itself is tubular, and arches rapidly caudad to a 

 point over the tectum, then curving more rapidly cephalad, 

 between the hemispheres, is slung, as it were, in the 

 membrane connecting them. The structure is like that of 

 reptiles, varying much in different localities by the greater 

 or less development of certain elements. In characteristic 

 portions, there is, first, the wall of connective tissue; seated 

 upon this are slender cells, fibrous in character, which 

 support small granulal- nuclei in several series, and centrally 

 a larger nucleus beyond which the cell extends as a long 

 narrow flagellum projecting into the cavity. The appearance 

 is as though the single stalk supports nuclei of both sorts, 

 though this may be an illusion. Nerve fibres may be followed 

 in the spaces between the cell bases, extending in the direc- 

 tion of the axis of the organ, and passing into the larger 

 nuclei. There can be no doubt of the nervous character of 

 the organ. 



A blood sinus closely invests the epiphysis, outside of 

 which is a second investment from the dorsal sac which 

 projects caudad to ensheath it. The walls of the dorsal sac 

 consist of a single-layered epithelium with long cilia or 

 flagella projecting into the lumen. Numerous plexiform 

 diverticles also project into the cavity. The fibres from the 



