256 HICKS, ON MR. ARCHER’S PAPER ON ALG. 
starch-granule, or of a vescicle, can be considered of any 
assistance whatever. 
Can the disposition of the chlorophyll? How, then, are we 
to arrange those forms where the whole contents are homo- 
geneous? How are we to place those whose contents are 
without any definite arrangement? It seems that but little 
value can be placed upon this in the majority of cases, to 
which any one who has observed the various arrangements of 
the contents in the same plant I think will agree. It is 
true that in some there are peculiar dispositions, as in 
Zygonema and its allies, and, when present, no doubt is of 
certain value ; but even in this case the contents may become 
homogeneous, as in conjugating; and then, supposing sub- 
division to take place, the contents of the resulting cells 
would become more or less homogeneous, and thus the spiral 
character lost. 
Can the mode of subdivision assist us? Before this can 
be answered we must find out in how many modes, and in 
what varieties of forms, this process can take place. Here 
is a vast field. Let us therefore inquire of nature in every 
stage of the life of a cell—in its active spring growth, 
during and after its period of conjugating, in its zoospore 
stage, and in the forms the zoospore may ultimately assume, 
in the autumn growth, and in the various stages the winter- 
resting spore may pass through before it reach again the 
parent form. Let nature be fully inquired of here, and I have 
no doubt an ample harvest will be the reward. Can the 
form of the cell be of any help? If it is found that the sub- 
divisions of a generally round form assume an oval, at any 
stage, and then revert to the round shape, what value can 
we put uponthe form? That this can be constantly observed 
is palpable to any one who will watch the segmenting gonidia 
of lichens and other plants. I need only refer again to the 
plate illustrating Mr. Archer’s paper. The varying forms 
of the divisions show that their form changes very strangely. 
This is observable in almost every Converfa, and the Des- 
midiz are good examples. Supposing Mr. Archer had carried 
his observations as Cohn has done in Protococcus pluvialis, 
it is highly probable that as diverse forms would have been 
found. 
Upon what, then, are we to fix? No other answer seems 
practicable but that which I have already indicated, namely, 
upon the gradations assumed during its whole life-history. 
If it be asked, how can this be attained? it must be honestly 
answered, with much labour and careful observation; better 
trace one form out well than endeavour to attain an appa- 
