98 ON THE SEXUAL ORGANS OF THE CYCADACEA. 
completely analogous to the arehegonia. The embryo-sae of Gymno- 
sperms holds, therefore, the same position as a spore which remains 
contained within the sporangium ; the prothallium, which it produces, 
does not make its appearance externally; the fertilizing matter, in 
order to reach the archegonia, has to make its way through the tissues. 
The corpuscles, however, indicate by their numerous vesicles, of which 
only a single one is fertilized, a much more complicated condition 
than exists among the vascular Cryptogams. In these, or at any rate 
in the Ferns, there is only a single vesicle, the parent cell of the em- 
bryo, or rather of the pro-embryo. 
Hofmeister sees, rightly, a great distinction in the fact that in Gym- 
nosperms fertilization takes place, as in other Phanerogams, by means 
of a pollen-tube, whilst among the vascular Cryptogams this function 
is performed by spermatozoids. e contrast is certainly very marked, 
anatomically, but it seems less so from a physiological point of view. 
The matter which the male element conveys into the female element, 
through which it becomes the seat of a new vegetative evolution, is really 
of an analogous kind in the two cases. The difference affects more the 
external conditions of the function. Among the Phanerogams, an en- 
tire cell, the pollen-tube, deprived of its secondary envelope, moves 
towards the female cell, to which its fertilizing fluid must be transmitted 
by osmotic penetration. Among Cryptogams there are numérous se- 
condary cells (spermatozoids) which proceed from the antheridium, and 
which—by means of the power of progression possessed by them, and 
under the influence of surrounding conditions—insinuate themselves 
into the archegonium, and penetrate into the interior of the female 
generative cell. But as to an essential and fundamental opposition be- 
tween the contents of the pollen-tube and those of the spermatozoids, 
one cannot admit its existence after having learnt, especially from the 
researches of Schacht, to understand the nature of spermatozoids better.* 
We must add to this, that amongst the Conifere, it is not rare to see 
the pen c penetrate into the corpuscle after having perforated 
its summ 
The AR T which thus exists between the vascular Cryptogams 
* Schacht, * Die Spernia im pierre. 1864.’ —I have no know- 
ledge of precise data the chemical properties of spermatozoids. It 
would not be without ione: o Berai if phosphorus Deag ud them in as 
great proportion as Sec in doce (compare Corenwinder in the Ann. des 
Sciences Nat. 4me sé ^ 
