344 Mr. A. Henfrey on the Progress of Physiological Botany : 
of this latter display, often at a very early period, new minute 
cellules filled with a granular substance, occurring in an inde- 
finite number and sometimes appearing very regularly arranged. 
They become more and more distinct, and in the mature condi- 
tion generally fill up the parent-cell, so that this appears lke a 
sac distended with round granules. By reciprocal pressure they 
acquire a parenchymatous aspect. When an organ of this kind 
has reached the proper stage of maturity, it bursts spontaneously 
at the apex and discharges an indefinite number of minute round 
cellules enveloped in mucus. In some cases | have observed an 
uniformly distributed, rhythmical motion of the whole discharged 
mass. But the cellules usually exhibit a motion round their 
axis very soon after their emergence ; each of them unfolds a spi- 
ral filament, which generally remains connected with the deli- 
cate cellule by its posterior extremity, and advances with an ac- 
tive revolution round its axis. 
“As Nageli has well described the very various movements of 
these spiral filaments, it appears to me unnecessary to discuss 
this subject here. But I must observe that I have seen on the 
clavately swollen, anterior extremity of the spiral filament, de- 
licate motile cilia of considerable length, which however are only 
to be perceived distinctly with the help of the strongest artificial 
illumination. They are best observed when the rapid revolution 
of the filament is slackened. Then about six such cilia may be 
observed on each, which after the cessation of the motion of the 
spiral filament also gradually cease to move, and either stiffly 
surround this or become in part so applied upon it that it is 
almost impossible to detect them. The motion of the cilia en- 
dures longer than that of the filament, and not unfrequently 
shortly recommences. The form of the spiral filament cannot be 
perceived distinctly either during active motion or after this has 
ceased, because in the first case. the form is altered by the con- 
tinual change of the convolutions and the motion of the cilia,— 
im the latter by the cessation of the revolution, as the filament 
then contracts in irregular curves. It is necessary therefore to 
seek out a moment when the spiral filament, sufficiently mature, 
_ still remains in its cellule, and occurs on a free space in the pre- 
paration. In such cases it exhibits either two or three convolu- 
tions, or appears wound in a semicircle with the swollen extre- 
mity applied to the wall. The cilia are not then perceptible. 
This position often gives a very well-defined figure. It is di- 
stinctly seen that the spiral filament incloses a longish vesicle in 
the above-mentioned clavate thickening of the anterior extre- 
mity. The thick end diminishes gradually down into a filiform 
tail which bears a slightly swollen knob at the end. 
