224 MONOCYSTEÆ.
Hab. High Be ech: A . H. H. Penzance: Mr. Ralfs.
Bogs at Fisher’s Castle: Mr. Jenner.
This very beautiful species is by no means common. I t
inhabits generally ponds on commons and other exposed situations.
8. L y n g b y a v e e m ic u l a e i s Hass.
Plate L X . Fig. 5.
Char. Filaments very mucous, tenacious, and o f a yellowish
green colour, finer than those o f the preceding species.
Cells twice or thrice as long as broad. Fndochrome
rarely filling the cavity o f the cell.
Hab. High Beech : A. H. H. Penzance: Mr. Ralfs.
Sussex: Air. Jenner.
A common species in boggy pools.
9. L y n g b y a p r o l i p ic a Grev.
Plate V I I I . F ig. 4.
Char. Filaments exceedingly slender, entangled, purple, very
broadly effused, floating.
Grev. Crypt. Fl. t. 303.; Harv. 1. c. p. 370.; also in Manual,
p. 1 6 0 .
Hab. In the loch of Haining, Selkirkshire, October to
A pril: Dr. Greville.
“ P lan t extensively diffused, forming a floating stratum,
of a rich purple colour. Filaments extremely slender, entangled,
somewhat rigid, yet flexible, entirely destitute of
attachment, and free from any mucous layer. Annuli from
the minuteness of the filament almost inconspicuous.”— Grev.
Note.— The following marine Algæ I regard as members of the genus
Cladophora,— C. pellucida, C.rectangvlaris, C. Hutchinsioe, C. diffusa, C.
nuda, C.rupestris, C. loetevirens, C.flexmsa, C. gracilis, C. réfracta, C.
albida, C. lanosa, C. uncialis, C. glaucescens, C. arcta, C. oeruginosa, and
C. riparia ; while in Aplonema I place the subjoined Confervoe,— arenicola,
svtoria, Linum, crassa, implexa, idothrix, arenosa, melargonium, oerea, col-
labens, bangio'ides, Youngana, and clandestina.
F am . XI. HYDRODICTYONEÆ.
21. H Y D R O D IC TY O N Roth.
Char. Cells arranged in the form o f a pentagon, an aggregation
o f a number o f these pentagonal meshes, going to
form an entire plant. Zoospores numerous in each cell,
and uniting together before the absorption o f the parent
cell membrane.
Derivation. From vBwp, water, and Siktvov, a net.
1. H y d r o d ic t y o n u t r ic u l a t u m Roth.
Plate L V I I I .
Char. Same as those of the genus.
Harv. in Hook. Br. Fl. vol. ii. p. 359. Conf. reticulata,
F . B. t. 1687.; Dillw. t. 97.; Vauch. Conf. d’Fau douce;
Harv. Manual, p. 1 4 0 .
Hab. In ditches and pools in the midland and southern
counties of Fngland. In a pond in the Botanic Garden
a t Cambridge, where it has existed for many y e a rs :
Rev. Prof. Henslow. Not found in Scotland or Ireland
hitherto.
Hydrodictyon utricidatum is one of the most remarkable
of the freshwater Algæ. The credit of the discovery of the
singular reproduction of this species is due entirely to
Vaucher, whose account of it is so clear and well expressed
th a t I cannot do better than translate his remarks : — Each of
the fine filets (cells) which form the pentagon begins to swell
a little, principally at the extremities, then it is separated
from the others not by a rupture, properly so called, but hy
Q