and its Nucleus in Chara verticillata. 15 



the " secondary nucleus in the parent-cell of the spore of Ant ho- 

 ceros^J^ 



Having thus briefly stated, as far as I am aware, the limits of 

 our knowledge respecting the development of the roots of Chara, 

 and the formation of the nucleus of the plant-cell, I will proceed 

 to the subject of this paper, premising a short description of the 

 first root-cell and its contents in the species of Chara mentioned, 

 that the reader may recognize without doubt the parts to which 

 I shall have occasion to allude. 



This cell is a long narrow cylindrical tube, with one end 

 attached to the nucule, and the other free. Its chief elements 

 are the cell-wall and " primordial utricle ^^ of Mohl. 



Of the cell- wall nothing more need be said here than that it 

 is as transparent, colourless, and apparently structureless, as 

 unstained glass ; but the protoplasm is composed of many organs, 

 which I will first enumerate and then describe in detail. Thus, 

 it is itself surrounded by a cell which we shall call the " proto- 

 plasmic sac;" then the protoplasm is divided into a fixed and 

 rotatory portion ; these again respectively enclose the nucleus, 

 '^granules,^^ and axial fluid; while those small portions of matter 

 which I have before designated as "irregularly shaped bodies f '' 

 are common to both. 



Protoplasmic Sac. — This sac I have only been able to demon- 

 strate satisfactorily by the aid of iodine and acids applied to the 

 fixed protoplasm when it is about to undergo division for the 

 second root-cell, in the way which will be hereafter mentioned. 

 Its existence, however, might be inferred, from iodine and acids 

 failing to produce any separation between the fixed and rotatory 

 portions of the protoplasm ; for these cannot be considered to be 

 in direct union, and therefore, unless supported in their relative 

 position by a membranous sac common to both, would most 

 probably present a line of separation under contraction. Again, 

 the "primary" nucleus ultimately becomes stationary in the 

 midst of the rotating protoplasm, and it also must be fixed to 

 something which is not only stationary itself, but is also carried 

 inwards with this part of the rotating protoplasm, when the 

 latter is condensed and made to leave the cell- wall by acids; for 

 the nucleus, or what remains of it, is at such times seen to be 

 enclosed in the general mass of contracted cell-contents. Lastly, 



* Idem, 1846, pp. 261 Si 262. — Himantidium pectinale (Kg.) affords a 

 good example of it among the Algse ; and in the same way I have seen it 

 in some of the cells projecting into the gum-cavities of the bark oiHyper- 

 anthera Moringa (Roxb.), the Horse-radish tree of India; that is, both 

 halves of the nucleus remaining opposite each other, on either side the 

 septum, after the latter has divided the old, from the new cell. 



t Ann. and Mag. Nat. Hist. vol. xvii. p. 106, 1856. 



