M. Miiller on the Development of Chara. 391 



completely inclose the central cell and prevent any access to it 

 from without (figs. 30 — 35). As a proof I have given a figure 

 (fig. 36) from these young fruits, which may be compared with § 2. 

 fig. 35. from them when ripe. In it the existence of the central 

 cell is distinct enough at the intercellular spaces. The prepa- 

 ration is placed upon its vertex, and thus the pressure of the five 

 terminal cells against one another may be distinctly seen. 



This central cell forms the commencement of the nucleus, and 

 the five external with the five* terminal cells form the young 

 sporal sac. The sporal membrane is not yet developed. 



All parts of the fruit now become elongated, and as they in- 

 crease, the cells of the sporal sac, which continue to become utri- 

 cular, assume another position, i. e. they turn spirally around the 

 nucleus, whilst in their youngest state they had merely an up- 

 right position. 



When the fruit has arrived at the limit of its longitudinal ex- 

 tension it expands spherically, becoming at the same time tilled 

 with cells. These are again formed from cytoblasts, as may be 

 seen in fig. 32, and it is probable that in the new cells thus 

 formed new ones are again formed and so on, until the process 

 of cell-formation ceases from the transformation of all the cells 

 into starchy matter. This is a complete confirmation of Schlei- 

 den^s observations on cell-formation in the embryo. I was not 

 satisfied however by observing merely the true commencement 

 of this formation (fig. 32) ; for the cells of the sporal sac be- 

 come so speedily turbid, that the interior is rendered quite un- 

 distinguishable, nor could I succeed in extending my observa- 

 tions by dissections. 



When the fruit has attained its proper dimensions the remain- 

 ing cells become thicker ; the primordial utricles, which were at 

 first scarcely perceptible, now become distinct, and the contents 

 of the cells are formed. These are at first of a reddish colour ; 

 they continue to become more intense, and subsequently become 

 brownish yellow and green, which colour they retain. In the 

 meantime the nucleal membrane has become thickened, and is 

 now surrounded by another strong brownish membrane. This is 

 the spore-membrane. It is merely the intermal membrane of the 

 spore-sac thickened, and may be subsequently completely sepa- 

 rated from it. Thus are explained its perfectly homogeneous 

 structure, flattened form, spiral windings and the interruption of 

 this winding, the upper angles of which are always the most 



* According to Meyen (Physiolog. vol. iii. p. 394) there are sometimes 

 six sporal sac cells. 1 have never seen tliem myself. If however it be true, 

 it is the same, as when we find the central utricle surrounded by six, seven, 

 eight or more cells. Hence here the minimum is six, in the former case 

 live. 



