DEC 10 1892 



DEVELOPMENT OP THE OPTIC NERVE OF VERTEBEATES. 85 



On the Development of the Optic Nerve of 

 Vertebrates, and the Choroidal Fissure of 

 Embryonic Life. 



By 



Richard Asslictoii, M.A., 



Demonstrator of Zoology in the Owens College. 



With Plates XI and XII. 



In the ' Anatomische Anzeiger^ of 28th March, 1891, 

 Froriep described, in a somewhat brief manner, the way in 

 which the fibres of the optic nerve are developed in the em- 

 bryo of Torpedo ocellata. The paper contains twelve out- 

 line figures, which satisfactorily indicate that in the case of 

 Torpedo ocellata at least certain fibres of the optic nerve 

 arise from nerve-cells or neuroblasts situated in that portion 

 of the optic cup which will form the retina at a later stage of 

 development. 



Herr Froriep is, I believe, the first who has published any 

 figures in support of what is not altogether a new idea. In a 

 foot-note to the above-mentioned paper Froriep remarks that 

 Keibel had previously described the centralwards growth of 

 the fibres of the optic nerve from the retina in reptilian 

 embryos. 



The original statement of KeibePs was in the form of a 

 communication to a meeting of the Naturwissenschaftlich- 

 medicinischer Verein in Strasburg, and, as I understand from 

 a letter from Herr Keibel himself, there is not a fuller pub- 

 lished account than that which appears in the ' Deutsche 



VOL. XXXIV, PART II. — NEW SBR. G 



