Gi
i.
;
:
(H
I.! '
t!
l i l : ;J. ;
I. ,
•i' i!: I
i . 'f '
deserve the names of all those who have made the Freshwater
Algæ the ohjeet of their study. I had intended also to have
entered upon the consideration of the subject of classification,
and to have remarked on those which have hitherto been ¡iro-
posed. I have been pi’evented from fulfilling these intentions
by the fact that this work has already greatly exceeded the
limits originally proposed for it. Should it be destined, however,
to reach a second edition, chapters devoted to the consideration
of these two questions might, by the adoption of a
smaller type, be inserted with advantage. So much for the
omissions from the work. I would now refer to a super-
fiuity, and beg the Header’s indulgence for what I fear,
without explanation, might be deemed an unnecessary intrusion
on his notice, the attachment of the writer’s name
either to each new species or to those Avhich for the first time
have been referred to other genera. This was done under the
impression that the practice was usual and customary.
That much still remains to be effected ere our knowledge
of the Freshwater Algæ shall be in any thing like a complete
state is evident from the number of species which for the
first time are introduced in this work. So numerous are these,
and so closely do many of them approach each other, that
there are some, I fear, and especially such as have not made
the Algæ their study, and who therefore are scarcely in a
position to declare what amount of difierence is of specific
value, who will be ready to assert, that the species have been
multiplied on insuiRcient grounds. L e t such pause ere they
advance such an injurious assertion, which, like all assertions,
it is an easy matter to make, but more difficult to substantiate
; let them first bestow upon those species the care,
labour, and anxiety of their founder, and then their opinion
will be rendered valuable, and injustice be inflicted on no
party.
That superficial observers should arrive at tlie conclusion
th a t nearly allied species are states of one and the same production
is not so surprising, when we consider that the characters
which distinguish species amongst the Algæ are frequently
not very obvious or prominent, and since even men
of acknowledged skill and powers of observation have even
fallen into the error of asserting that a number of distinct
species are conditions of one and the same plant. Thus
M. G. Thuret, Avhose papers on the locomotive organs of the
spores of the Algæ are the most interesting and important of
any which have ever appeared on the Algæ, has committed
this mistake in reference to the Vaucheria, declaring that all
the species are states of one and the same production, and
comprising them all under the name of Vaucheria Ungeri: for
a refutation of this position, see the figures of the species of
this genus contained in the present work. Other observers,
again, even go further than this, not allowing the Vaucheria
to rank as species at all, but stating th a t they are merely
stages in the growth of mosses. Statements of this transformation
of Algæ into mosses, &c., are wholly without foundation,
and wholly undeserving of credit.
The end is drawing near. How strongly are Ave mortals the
creatures of hab it and association ! Avith Avhat reluctance do
Ave q u it a place, a companion, or a p u rsu it w ith which we
have been long connected, and it may be no t altogether
agreeably so ! T h e prisoner of Chillon felt reg re t a t q u ittin g
th e prison of Avhich for so many years he had been th e solita
ry in h ab itan t : each o f us can call to mind the pain Avhich
Ave have experienced in leaving a companion Avith Avhom Ave
have been long associated, even though th a t companion may
n o t have been really esteemed by us; and I must confess th a t
I cannot banish some feeling of reg re t a t th e conclusion of
th is undertaking, which has for so long a time interAvoven
itse lf Avith my thoughts, notwithstanding th a t th ere are several
considerations which render th e completion of th e ta sk a subje
c t of congratulation.
Alth o u g h in a fcAv days I shall cease to be occupied Avith
this Avork, th e in te re st Avith Avhich th e subject of which it
tre a ts has inspired me Avill no t have ceased. In th e fact
th a t I have devoted so much time to its consideration th ere
is no reg re t : I am still willing to devote more to it ; and I
shall gladly a t all times avail myself o f th e correspondence of
all or any a v I i o may take an in te re st in the Algæ, and will