72 
Druce, on Confervoideoe. 
a ruptured cell of Vaucheria assume the form of young 
encysted fronds of Pediastrum so nearly^ that had I not 
myself seen the process^ I should have had no doubt in so 
considering them ; the contents of Cladophora in like manner 
bear an exact resemblance to young Palmellse. I might con- 
tinue the list of these false appearances ; but^ not to multiply 
instances^ I would just remark that in Spirogyra^ the instant 
a cell is injured^ or the density between the contents and the 
surrounding medium altered^ the spires become flaccid and 
exhibit a disposition to separate into globular aggregations of 
chlorophylls,, and around each will be found a transparent 
protoplasmic layer. As this becomes inspissated^ it assumes 
the appearance of a true cellulose envelope, and may become 
produced into stellate processes ; and thus the history of many 
phenomena assumed to be connected with reproduction may 
be elucidated. T have no hesitation in asserting that almost 
all the obscure encysted bodies of algologists are to be 
accounted for in this wise. Again, in decaying cells, it is not 
unusual to find the contents resolved into a fibro-molecular 
mass, exhibiting a motion very similar to the- swarming in 
Desmidese ; this is doubtless the ordinary molecular motion, 
but it is very deceptive. The second class of difficulties is 
formidable to the physiologist and practised observer, and 
consists in this (in the words of the authors of the Micro- 
graphic Dictionary^), viz., the great apparent diversities that 
occur in the physiological phenomena presented by what at 
first appear like identical structures. I shall not touch upon 
these now in detail, as we shall have to dwell upon some of 
them at a later stage in our inquiry, but pass on to con- 
sider, first, the premises upon which, in the reproduction of 
Confervoid Algse, observers may hope to arrive at a right 
conclusion. To do this effectually, we must, I think, first 
look upon the distinctive peculiarities of the class before us, 
as bearing upon the phenomena we should expect to find 
connected with their reproduction; and this we may do 
without departing from legitimate analogy. These are the 
extraordinary extent of germ capacity conferred by a single 
generative act, and the continued nisus to vegetative multi- 
plication rather than to generation, so long as favourable 
conditions are supplied ; the independent vitality of the com- 
ponent parts of even the higher families, and the complete 
individuality of the phytoids of the lower ; and lastly, the 
great resemblance, both materially and physiologically, be- 
tween the protoplasm of the Algae and the sarcode of the 
lower animals. From these characteristics we may infer, first, 
that in many species the true generative act would be com- 
