418 Dr. Hanstein on the Fecundation 
the four cells. The process is completed in from eighteen to 
twenty-two hours. Soon afterwards the solid exosporium of the 
androspore breaks up, and the contents enclosed by the delicate 
inner membrane escape ; the contents either burst the membrane 
during their escape, or form a transparent spherule from which 
the daughter cells issue by degrees and set free the spermato- 
zoids. 
These have previously been in whirling motion; they burst 
their mother cells singly, and hurry from them with the rapidity 
of an arrow. Lach spermatozoid consists of a corkscrew-like 
filament, to the last remarkably large turns of which a large 
globular vesicle adheres; the latter contains numerous starch- 
granules in a clear fluid, and resembles an independent cell 
surrounded by a sufficiently firm membrane. This is by no 
means a part of the mother cell, which, on the contrary, remains 
behind empty after the escape of the spermatozoid. The screw- 
like filament has twelve or thirteen turns; it is very closely 
twisted at the apex, and is beset, especially on the lower and 
wider turns, with numerous very long cilia, which, when bent 
forwards in swimming, often project beyond the tip of the screw. 
In the meantime the prothallium with the archegonium has 
been developed on the macrospores. Even before the escape of 
the macrospore, its vertex, inflated in the form of a wart, is filled 
with yellowish finely granular plasma, while the rest of its space 
contains the well-known large starch-grains, oil-drops, and pro- 
teme substances. Several hours after the escape of the spore, 
this lentiform mass of protoplasm is still undivided by any per- 
ceptible septum from the rest of the inner space of the spore, 
and is therefore not a complete cell; but in about five or six 
hours it 1s cut off by a proper cellulose membrane. Soon after- 
wards its plastic contents separate into a roundish central prin- 
cipal mass and a peripheral layer which is thicker towards the 
free upper surface ; the latter then gradually divides into smaller 
and smaller portions, which surround the central mass in a 
single layer. The cell-body thus sketched out, but not com- 
pleted, breaks up at the slightest touch ; but subsequently first 
the central and finally the peripheral parts surround themselves 
with resistant cell-walls, which enter into close mutual con- 
nexion. 
The central cell is then the primary cell of the nascent arche- 
gonium, the mother cell of the germ; the peripheral cells form 
the prothallium. In the middle of the basal surface the central 
cell is sometimes in immediate contact with the septum between 
the prothallium and the interior space of the spore, and is there- 
fore excentric. Hxactly at its vertex four regularly placed cells 
soon exceed the others in size, and rise into a wart, each of them 
