PARIETAL SENSE-ORGANS OP GEOTRTA. 27 



strnctiires of the true fishes do not tend to confirm the theory 

 that the epiphysis of the ancestral vertebrates was connected 

 with a median unpaired eye." 



If we once recognise the paired origin of the parietal 

 sense organs^ the fact that a j)aired pineal foramen occurs in 

 the ancient Titanichthys need cause us no surprise. 



Reference List of Literature. 

 (For furllier references vide Studnieka, 2.) 



1. Dendy and Olliver. — "On tlie New Zealand Lamprey," ' Transactions 



New Zealand Institute,' vol. xxxiv, 1902. 



2. Studnicka. — " Die Parietalorgane," in Oppel's ' Lelirbuch der vergleich- 



enden mikroskopisclien Anatomic der Wirbellhiere,' part v, Jena, 1905. 



3. Dendy, — " On the Development of the Parietal Eye and Adjacent Organs 



in Sphenodon (Hatteria)," 'Quart. Journ. Micr. Sci.,' vol. xlii, n.s., 

 p. Ill, 1S99. 



4. Gaskell. — "On Die Origin of Vertebrates from a Crustacean-like 



Ancestor," ' Quart. Journ. Micr. Sci.,' vol. xxxi, n.s., p. 379, 1890. 



5. Dendy. — "On a Pair of Ciliated Grooves in the Brain of the Amnioccete, 



apparently serving to promote the Circulation of the Fluid in the Brain- 

 cavity," ' Proc. Hoy. Soc. Lond.,' vol. Ixix, 1902, 



6. Sargent, — "The Optic Reflex Apparatus of Vertebrates for Short- 



circuit Transmission of Motor Reflexes through Reissner's Fibre; its 

 Morphology, Ontogeny, Phylogeny, and Function." Part I — "The 

 Fish-like Vertebrates," 'Bulletin Mus. Comp. Zool. Harvard College,' 

 vol. xlv, No. 3, 1904. 



7. Studnicka. — "Sur les Organes parietaux de Petromyzon planeri," 



' Sitzungsber. der Kg. Ges. d. Wissensch. in Prag,' 1893. 



8. Cameron. — " On the Origin of the Pineal Body as an Amesial Structure, 



deduced from the Study of its Development in Amphibia," ' Proc. 

 Roy. Soc, Edin.,' vol. xxiv, part 6, 1902-3. 



9. Cameron. — " On the Origin of the Epiphysis Cerebri as a Bilateral 



Structure in the Chick," ' Proc. Roy. Soc. Edin.,' vol. xxv, part 2, 

 1903-4. 



10. Cameron. — " On the Presence and Significance of the Superior Com- 



missure throughout the Vertebrata," ' Journal of Anatomy and 

 Physiology,' vol. xxxviii, 1904, 



11. Dean. — " Fishes, Living and Fossil," ' Columbia University Biological 



Series,' New York, 1895. 



