60 Journal of Comparative Neurology. 



7. The pineal in a stage corresponding to 24-26 days of 

 Iguana, shows traces of pigment that appear to vanish again 

 afterwards. 



8. In an embryo of Iguana nerve bundles from the dienceph- 

 alic roof, entirely similar to the parietal nerve, enter the post- 

 erior part of the pineal. 



9. On the end of the proximal pineal of an Iguana embryo 

 and in an adult a secondory pigmented pineal eye is developed. 



Klinkowstrom drew the following homologies between 

 Iguana and Petromyzon : 



Iguana. Petromyzon. 



1. Parietal nerve. 1. Ventral eye vesicle. 



2. Pineal eye and distal part of 2. Dorsal eye vesicle, 

 the pineal evagination. 



3. Proximal part of the pineal 3. Pineal stalk, 

 evagination. 



4. Right parietal nerve. 4. 



5. Left parietal nerve. 5. Left parietal nerve. 



6. Parietalcentrum. 6. " Zirbelposter. " 



7. Post-pineal nerve. 7. Nerve filaments from the re- 



gion of the post commissure 

 to the dorsal eye vesicle. 

 Beraneck ! (5-87) in his first work, concluded that the pari- 

 etal eye is derived from the primitive epiphysis. In his second 

 work (5— '92) he described two stages of embryos of Anguis 

 (15 and 24-27 mm.) in which the vesicle was already discon- 

 nected from the proximal epiphysis. In the two stages Bera- 

 neck followed the course of the parietal nerve from its origin in 

 the roof of the diencephalon to its entrance into the retina of 

 the parietal eye. Throughout its course this nerve presents the 

 relations to the proximal part of the epiphysis described by 

 Francotte. From the fact of the existence of a separate parie- 

 tal nerve distinct from the epiphysis and connecting the parietal 

 eye directly with the roof of the diencephalon Beraneck con- 

 cluded that the parietal eye is not a diverticle of the distal part 



^ide KlinkowstrOm. 



