Reprinted from the Quarterly Journal of Microscopical Science. 



ON THE DEVELOPMENT OF THE OPTIC NERVE OF 

 VERTEBRATES, AND THE CHOROIDAL FISSURE OF 

 EMBRYONIC LIFE. 



By Richard Assheton, M.A., Demonstrator of Zoology in the 



Owens College. 



With Plates VIII. and IX. 



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 embryo of Torpedo ocellata. The 

 paper contains twelve outline 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 Keibel's was in the form of a communi- 

 cation to a meeting of the Naturwissenschaftlichmedicinischer Verein 

 in Strasburg, and, as I understand from a letter from Herr Keibel 

 himself, there is not a fuller published account than that which 

 appears in the ' Deutsche medicinische Wochenschrift,' 7th February, 

 1889, p. 115, which is as follows: — " Ueber die Entwickelung des 

 Sehnerven. — Bei alien Amnioten bilden sich die Nervenfasern in dem 

 unteren, mit der Netzhaut-anlage in Verbindung stehenden Theil 



