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 areclosely packed together.

The contents are originally homogeneous and muci-laginous. In this may be perceived globular utriclesor solid corpuscles, probably analogues of the nucleoliof the nuclear utricle. Sometimes the homogeneouscontents subsequently become finely granular. Chloro-phyll-granules are occasionally formed in them. In theIlhizocarpeae* they also contain starch-globules (?). Ata later epoch a spermatic filament,! composed of albu-men, is produced in each of these utricles.

B. Nucleoli (Kernchen).

The nucleoli were formerly regarded as solid bodies.I have already remarked upon this, some time ago, thatcertain phenomena connect themselves readily with thehypothesis 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 alwayspresent themselves with a very definite border. More-over, it is sometimes possible distinctly to perceive onthem a membrane different from the contents. The con-tents are not always solid; they frequently exhibit oneor 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 Rhizocarpeae, loo. cit.

f Nageli on the Moving Spiral Filaments (spermatic filaments) in Ferns .( Bewer/liche Spiralfaden, &c.) Sehleiden n. Niigeli’s Zeitschrift f. wiss.Bot., ’Heft i, p. 174 (1844).

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