30 Mr. H. J. Carter on the Development of the Root-cell 



cilia disposed on the inner surface of the protoplasmic sac, in 

 like manner to those which appear to exist in the abdominal 

 cavity of Vayiidcola crystaUina, and which have been seen and 

 drawn by the Hon. and Rev. S. G. Osborne, and confirmed by 

 Mr. Jabez Hogg, in Closterium Lunula^. 



By the latter observation I do not mean it to be inferred, that 

 I think the backward and forward, &c. motions of the corpus- 

 cles of Closterium, Simrella splendida (Ehr.), and Spirogyra, are, 

 altogether, thus produced ; for in the two latter organisms they 

 seem to be borne along in or upon minute mucus-threads 

 which creep over the internal surface of the primordial utricle, 

 or stretch across to the suspended nucleus. In the terminal 

 cells of the filaments of Spirogyra, especially, the advancing 

 point of these threads may often be seen, as well as the end 

 of the line of molecules trailing after them ; and several such 

 threads may also be seen in motion en masse, indicative of the 

 whole of the internal part of the primordial utricle being com- 

 posed of them, unless they form a particular structure of them- 

 selves. It has lately struck me too, while watching Surirella 

 splendida, that the motion which is seen in the corpuscles of its 

 interior is precisely similar to that of foreign bodies over its 

 surface, which I have endeavoured to prove by analogy to depend, 

 in the Diatomece generally, on the presence of a transparent 

 envelope endowed with locomotive and prehensile power f. 



It might be said, perhaps, by some, that in the pi-esent state 

 of our knowledge, the comparison between a plant and an animal 

 is not allowable ; but the answer to this respecting Amceba is, 

 that there is nothing on the animal side of this organism that 

 ofi'ers for comparison equal to the organisms on its vegetable 

 side, taking it even generally or particularly. Again, it might 

 be said that I was formerly of opinion that the rotating proto- 

 plasm circulated round the cell by itself; but I was then not 

 aware of the existence of the protoplasmic sac or a fixed mem- 

 brane inside the root-cell, on the apparent absence of which this 

 view was chiefly grounded. Lastly, it might be said that I 

 formerly tried to prove that the " gonidia " developed from the 

 Rhizopodous cells of the protoplasm were the offspring of a para- 

 site, and now I have hinted that they may be found to be deve- 

 lopments of Chara itself. Proof of the latter, however, is very 

 remote; but when we find that there exists an intimate analogy 

 between the nucleus of the cell of Chara and that of this Rhizo- 

 podous cell, as well as that of Amoeba, &c., both in form and, 

 probably, office, and that the nucleus of the Rhizopodous cell 

 divides up into granules for the production of the "gonidia'^ 



* Quart. Jonrn. Microscop. Sci. vol. ii. p. 234, 1854. 

 t Ann. and Mag. Nat. Hist. vol. xviii. 



