Sorensen, Study of Epiphysis and Roof of Dicnccplialon. 1 69 



opment, and, as already remarked, to call these sac-like project- 

 ions epiphyses is absurd, as their structure and position prove 

 their plexiform origin. From our study we would give the fol- 

 lowing scheme as covering all the forms of the roof of the dien- 

 cephalon. 



Post-commissure. 



Epiphysis. 



Supra-commisure. 



-c, . 1 • f dorsal-sac. 



rost-paraphysis < , 



r r J \ plexus. 



Velum. 



Pre-paraphysis. 



For schemes given by others, see Osborn, p. 27; Burck- 

 hardt, p. 42, and a short resume of his recent work in this num- 

 ber; Klinkowstrom, p. 60; Kupffer, p. 61, and a resume in this 

 number of his recent work. 



BIBLIOGRAPHY. 



98. Gage, Susanna Phelps. 



'93. The Brain of Diemyctylus viridescens and comparisons with the Brain 

 of Amia and of Petromyzon. The Wilder Quarter Century Book. 



99. Kupffer, C. von. 



'93. Die Entwicklung des Kopfes von Acipenser sturio an Medianschnitten 

 untersucht. Studien zur vergleichenden Entwicklungsgeschichte des Kopfes 

 der Kranioten, i Heft, Miinchen und Leipzig. 



ABBREVIATIONS. 



ant. — hippocampal commissure. Is. — lens. 



bl. sin. — blood sinus. pig. — pigment. 



cap. — capsule. ret. c. — retinal cells. 



ep. — epiph. — epiphysis. post. com. — post-commissure. 



epith. — epithelium. sup. com. — supra-commissure. 



EXPLANATION OF PLATES. 



PLATE XIII. 



Figs. i~2. Transverse sections of the epiphysis and related parts of Lepi- 

 dosteus. 



Figs. 3-4. Horizontal sections of the same. 



Figs. 3-6. Transverse sections of the epiphysis and related parts of Sea- 

 phirhynchus. 



