172 UTRICULAR STRUCTURES. 



The mode of origin of the spermatic cellules is unknown, 

 as also of the propagation. 



The shape of the spermatic utricles is globular or ellip- 

 soidal when they are free parenchymatous when they are 

 closely packed together. 



The contents are originally homogeneous and muci- 

 laginous. In this may be perceived globular utricles 

 or solid corpuscles, probably analogues of the nucleoli 

 of the nuclear utricle. Sometimes the homogeneous 

 contents subsequently become finely granular. Chloro- 

 phyll-granules are occasionally formed in them. In the 

 Rhizocarpea3* they also contain starch-globules (?). At 

 a later epoch a spermatic filament, f composed of albu- 

 men, is produced in each of these utricles. 



3. Nucleoli (Kernchen). 



The nucleoli were formerly regarded as solid bodies. 

 I have already remarked upon this, some time ago, that 

 certain phenomena connect themselves readily with the 

 hypothesis that they are utricles. \ The question is now, 

 whether there are grounds for this assumption. 



That the nucleoli are not mere aggregations of mu- 

 cilage, follows from the circumstance that they always 

 present themselves with a very definite border. More- 

 over, it is sometimes possible distinctly to perceive on 

 them a membrane different from the contents. The con- 

 tents are not always solid ; they frequently exhibit one 

 or more cavities; they are even frothy and granular, 

 like the contents of the nuclear utricles and the cells. 

 To these we may add the analogy with animal nucleoli, 

 which are likewise utricles, and the other utricular struc- 

 tures of the cell-contents. 



* Nageli on Riiizocarpese, Ipc. cit. 



f Nageli on the Moving Spiral Pikments (spermatic filaments) in Ferns. 

 (Bewegliche Spiralfaden, &c.) Schleiden u. Nageli's Zeitschrift f. wiss. 

 Bot., Heft i, p. 174 (1844). 



t Nageli on Cells, &c. ; Ray Translation, 1845, p. 250. 



