M. Miiller on the Development o/Chara. 329 



branches and the shoots soon formed strong membranes.] The 

 primordial utricle also follows this course until it is completely 

 drawn in. This also agrees with MohPs observations. We have 

 some striking proofs of it in the preparations of PI. VII. figs. 21, 

 22, 23, 24 and 26. In fig. 21 the preparation was treated 

 with iodine, and the primordial utricle has become retracted from 

 the walls of the cells ; but it is not completely separated, for it 

 is distinctly seen under the microscope to pass through both of 

 the cells. The part which was not contracted appeared much 

 more transparent and clear than the other portions. In PI. VII. 

 fig. 22 the apex is sliced longitudinally, and it is distinctly seen 

 how the secondary membrane projects into the interior, but has not 

 yet come into contact : I have observed this once only. In fig. 23 

 the apex is seen to be entirely separated by constriction : it appears 

 exactly as if it passed into the previous articulation. The same 

 occurs in fig. 24. The preparation was treated with nitric acid, 

 and the primordial utricle of the lower cell has separated from 

 the cell- wall, so as to resemble an open utricle, into which we can 

 easily see. Fig. 26 exhibits the two extremities of the primordial 

 utricle so remarkably torn, and agreeing in this particular so much, 

 that we cannot help believing that they must once have been con- 

 nected. Moreover I have frequently perceived this form. Are we 

 now authorized to conclude from these transitions that there occurs 

 a division of the cells ? I think we are ! and I could have added 

 many more sketches of preparations which are in my manuscript. 

 One thing appears to me remarkable, viz. that all other parts of 

 the plants are certainly formed from cytoblasts, and in this in- 

 stance we have a division of already formed cells. However, I 

 see no other deduction from the observations than the division of 

 the cells. 



It is remarkable in the primordial utricle, that it (as in fig. 24) 

 appears as completely separated as if it had been cut with a 

 knife; it also seems not to be so important in these cells as in 

 those formed from cytoblasts. Double septa formed from secon- 

 dary membranes (one belonging to each cell) are in tolerably 

 close contact and perfectly close the separate cells. Now as the 

 primordial utricle is firmly attached to this, the interior of the 

 cell is closed as regards the regular course of the circulation of 

 the sap. And when it is completely absent in the old cells, as 

 Mohl observed, this from its gradual absorption could not pro- 

 duce any interruption to the cell-life. 



[To be continued.] 



Ann. ^ Mag, N. Hist. Vol. xvii. 2 A 



