DrucEj on Confervoidece. 
75 
antheridia of Vaucheria. It will be more consonant with 
my purpose to consider tlie Confervacese and Zygnemacese 
together as one class_, waiving any precedence in point of 
classification between them in virtue of their near relation 
one to the other in vital phenomena ; and that this is nearer 
than is generally imagined, I desire to show, by weighing 
the value of conjugation (the prominent characteristic of 
the latter family), as a true generative act, complete in itself. 
I should have great hesitation in propounding an assertion so 
heterodox, if I were not backed by the weighty authority, 
Schleiden, but I truly believe that conjugation is in no case 
or class essential ; the obvious and rough analogy presented 
by the coalescence of two cells having blinded many observers 
to the evidence upon the other side. 
In reference to Spirogyra, Schleiden says, ^^I have ob- 
served the following cases, which prove how inessential this 
process really is. Two cells were combined with the papilla 
of a third cell, and thus arose four spores — one in each of the 
first-named cells, and two in the third. Three cells were 
combined, and the result was the formation of one spore in 
the space formed by the three papillse. Again, two cells were 
combined ; there appeared two spores, and a third spore in 
the cavity of the papilla. Two cells combined together, and 
here a spore was formed in each one. Another instance very 
frequently occurred, in which one cell that had a papilla, 
which did not combine with another, exhibited a spore formed 
within the cell. Finally, it sometimes happens, although but 
rarely, that a spore is formed without the cell having formed 
any papilla.^^ This paragraph I quote entire, because it 
afibrds, in better terms than I could have described, a com- 
plete epitome of my own experience. I have only to add 
that, having witnessed in many cases the endochrome in the 
very act of transference, I am certain that the assertion of 
Itsighsohn, that in one cell the contents are broken up into 
moving spiral filaments or antherozoids, is void of foundation ; 
in fact, that observer having been probably deceived by an 
injured filament, the disintegrated contents of which exhibited 
molecular motion, — a source of error referred to in my intro- 
ductory observations. The occurrence of non-conjugatory 
species in these Conjugatese is surely sufficient evidence ; and 
when, in addition to this, we find no approximation to this 
process among the multitude of Confervoidese, so closely allied 
in other characteristics, we may surely consider the case 
proved against its essentiality. 
The conjugation, so far as seen among the Diatomacese, 
strengthens this view ; for here we have the spores resulting 
