Dr. Sliarpey.
Lady Agnew.
J. A. Ilankey, Esq., F.L.S.
.T. AVoods, Esq., F.L.S.
AV. II. Harvey, Esq.
Kev. AV. S. Hore, M.A. F.L.S.
G. E. Dennes, Esq., F.L.S.
AV. C. Trevelyan, Esq.
General Irvine.
G. II. K. Thwaites, Esq., M.E. B.S.
C. Richardson, Esq.
G. S. Gibson, Esq.
E. J. Quekett, Esq., F.L.S.
Mrs. Stewart.
Dr. Graham, Prof. Bot. Edin.
J. Reynolds, Esq. Bot. Soc. Lond.
R. Ball, Esq., M.R.I.A.
S. AVallis, Esq., M.B.S.L.
J. Straker, Esq.
J . Hogg, Esq., F.L.S.
AV. B. Carpenter, M.D. F.R.S.
H. Deane, Esq.
R. Balloch, Esq.
T. J. Taylor, Esq.
Miss M. Ravenhill.
S. Simpson, Esq. F.B.S.E.
G. Booth, Esq.
J. Riley, Esq., M.B.S.L.
D. Stock, Esq., M.B.S.L.
Mr. E. Jenner, A.L.S.
P. G. P- Nelson, Esq., E.L.S.
J. Pym, Esq.
J. T. Mackay, Esq., M.R.I.A.
Rev. L. Jenyns, F.L.S.
G. B. Knowles, Esq., F.L.S.
Dr. Percy.
R. D. Alexander, Esq., F.L.S.
AV. Osborne, Esq., F.L.S.
R. Ranking, Esq., F.L.S.
AV. Bean, Esq.
D. Moore, Esq., A.L.S.
Dr. Pollexfen.
E. Stokes, Esq., E.R.S. and L.S.
Rev. N. Rolfe, A.M.
G. J. Lyon, Esq.
AV. J. Horry, Ph. D.
R. J. N. Streeten, Esq., M.D.
AV. Andrews, E sq , Secretary Dublin
Hat. Hist. Soc.
T. F. Bergin, Esq.
AV. H. Cullen, M.D.
Sir. O. Mosley, Bart. E.L S.
T. B. Hall, Esq., M.L.B.S.
Baron Delessert.
— AVebb, Esq.
AV. AV. Reeves, Esq.
J. Dalrymple, Esq.
G. M. Hutton, Esq.
J. Just, Esq.
J. Sidehotham, Esq.
R. A. Tudor, Esq.
R. Bell, Esq.
G. Rogers, Esq.
J. Hardy, Esq.
— Bladon, Esq.
— G. Blyth, Esq.
Sir J . Murray.
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Thos. Edmonstone, jun., Esq.
J. B. Estlin, Esq., E.L.S.
Sir P. G. Egerton, Bart., F.L.S.
J. Scouler, Esq., M.D. F.L.S.
G. P. AVright, Esq.
J . Lister, Esq.
J . AV. G. Gutch, Esq.
E. Forster, Esq., V.P.L.S.
R. Robinson, Esq., M.D. F .L.S.
F. Eagle, Esq., E.L.S.
AV. K. Loftus, Esq., E.G.S.
F. Sopwith, Esq.
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Dr. Lindley, P h .D . F.R.S. F.L.S.
Dr. Knapp.
Robert AVigham, Esq.
Robert Callwell, Esq.
INTRODUCTION.
A t the period when the researches hereafter to be detailed
Avere undertaken with a view to publication, viz., in the
spring of the year 1840, no department of Cryptogamie
Botany was in so unsatisfactory and obscure a state as that
of the freshwater Algæ ; the works and memoirs, comparatively
few in number, which had then appeared, either in this
country or on the Continent, abounding with descriptions
incomplete, inaccurate, or repetitions of the same productions
and facts under different forms and appearances.
That such should have been the case is not so surprising,’
when the minuteness of the objects composing the majority
of this fertile class of Nature’s exhaustless works is considered
(the individual parts of many of them being more slender
than the human hair), and when, also, the imperfection of
the microscopic instruments until recently employed in their
investigation, and their changing and fragile character, are
taken into account, these circumstances rendering a patient
and long-continued study of them necessary. I t nevertheless
must be regarded as somewhat remarkable, that a field so
rich in discovery and of such high interest, until very lately,
should have been so little explored ; and that such would
have been the case, was certainly not in accordance with the
expectations of Vaucher when he penned the following
remarks in the introduction to his eloquent and admirable