118 



Mr. E. H. Acton. Tlie Assimilation of [May 16, 



Fetromyzon appear to have no homology with these larval ganglion 

 cells.* The proof of this statement is impossible without figures. 

 I hope to show, in a fuller paper on the early development of the 

 central nervous system, that in Scy Ilium giant ganglion cells are 

 developed in deeper portions of the spinal cord, and that these cells 

 have exactly the situation and characters of the well-known giant 

 ganglion cells of AmjoMoxus* 



In the same sections of Scyllium embryos the two sorts of cells can 

 be seen ; the one deeply situated in the cord, and with well developed 

 processes, the other outside the nervous system, and greatly degene- 

 rated. 



I will here only remark that I cannot support Mayer's conclusions J 

 as to the fate of these giant ganglion cells, and defer a discussion of 

 his views until I have followed the history of these cells in Fetromyzon. 



1 may here point out, however, that Kleinenberg§ appears to me to 

 have been quite right when he suspected that the cells described by 

 Mayer might be analogous to certain sub-umbrellar ganglion cells in 

 the larva of LojpadorJiynchus, which " introduce " the development of 

 the ventral cord : and that, just as in the Annelid, the development 

 of the vertebrate central nervous system would appear to have been 

 initiated by a larval nervous apparatus outside the same. I propose to 

 discuss this question in a future paper. 



V. " The Assimilation of Carbon by Green Plants from certain 

 Organic Compounds." By E. Hamilton" Acton, M.A., 

 Fellow of St. John's College, Cambridge. Communicated 

 by W. T. Thiselton Dyer, C.M.G., F.R.S. Received April 

 20, 1889. 



(Abstract.) 



The recent synthesis of a true glucose (" Acrose ")|| by Fischer and 

 Tafel, and additions to our knowledge of the structure of dextrose 

 and leevulose by Kiliani,^[ &c, seem to render desirable fresh experi- 

 ments on the synthetical production of carbohydrate in green plants 

 from sources other than C0 2 (i.e., from organic compounds in which 

 C is already combined with H and 0). 



* The homology of the giant ganglion cells described by Fritsch in LopMus is 

 doubtful. 



f Vide the excellent figure (fig. 143) in Hatschek's ' Lehrbuch der Zoologie,' 

 p. 138. Probably Ampliioxus possesses a transient or larval nervous apparatus. 

 % Op. ext., p. 229. 



§ N. Kleinenberg : "Die Entstehung des Annelids aus derLarve von Lopadorhyn- 

 chus." 1 Zeitschr. Wiss. Zool.,' vol. 44, pp. 220—221. 



I! ' Deutsch. Chem. G-es. Berichte/ vol. 20, pp. 1088, 2566, 3384. 

 IT Ibid., vol. 19, p. 221. 



