gree of a voluntary character, and whether the explanation
given of the elevation to the surface of the waters of almost all
the Conferva is not sufficient to account for that of the Anahaina.
The explanation alluded to is the fact that during
respiration a gas is eliminated, the globules of which becoming
entangled in their filaments, renders them specifically
lighter than the water, and so causes them to ascend.
1. A nABAINA FLOS-AQUaE Borg.
Plate L X X V . Fig. 2.
Char. Filaments large, beautifullg moniliform, and variously
curved. Reproductive cells numerous, elongated, and fo r
the most part curved.
Nostoc flos-aqua Lyngh., Dan. p. 201. t. 68. Anahaina
flos-aqua B o ry ; Hudson, Flor. Ang. p. 604.; Light.
Scot. p. 999.; Harvey in Manual, p. 186.
“ This species attracted my attention when tinging with
its dehcate green hue the margin of the smallest (?) of the
lochs Maben in Dumfries-shire, or that nearest to Jardine
Hall (on the road from the village of Lochmahen), as I drove
thither on the 15th of August, 1838. The day was calm and
bright. My specimens tinge the paper with a verdigris
colour, and are quite dull, or wanting in any lustrous appearance.
This species is introduced here on account of its
having been erased of late years from the British Flora.
Hudson and Lightfoot included it without assigning to it
any British station or locality.” — Thompson. The reproductive
cells, which, as noticed in the definition of the
species, are curved to accommodate themselves to the various
curvatures of the threads are mostly solitary, and I have
never observed more than two contiguous to each other.
2. A nabaina lichenifoemis ? Bory.
P late L X X V . Fig. 4.
Char. Filaments not moniliform, minute, hut little curved.
Reproductive cells o f various sizes, oval, and occuri'ing
in series.
Bory, in Diet. Class, d. Hist. Nat. vol. i. p. 309.
llah. Neighbourhood of Dublin : Dr. Allman. County
Wicklow : Mr. Moore. Sussex : ilfr. Jenner.
There is no species hitherto recorded with which this can
possibly be confounded. The form of the reproductive cells,
the various size of these and their occurrence in chains or
series serving to mark it from all others.
3. A na ba in a im pa l p e b r a l is ? Bory.
P late L X X V . Fig. 3.
Char. Filaments minute, not moniliform, but little curved.
Reproductive cells large and quadriform.
Bory, in Diet. Class, d. Hist. Nat. vol. i. p. 309.
Ilab. Under a waterfall, co. Wicklow : ilfr. Moore.
This is also a very distinct species; the reproductive cells
are large, elongated, and in the form of a parallelogram, with
the angles slightly rounded; they are also usually solitary,
rarely in pairs. I t dries without gloss.
4. A nabaina constricta Hass.
P late L X X V . Fig. 9.
Char. Filaments very slender, not moniliform. Reproductive
cells much elongated, mostly solitary, small.
Hab. On mosses, Cheshunt: A.. H. H.
This species bears some resemblance to the preceding; the
reproductive cells are, however, not nearly so large as in it,
and are slightly constricted in the centre.
35. S PH iE R O Z Y G A A^.
Char. Stratum gelatinous, in which undulate articulated
unbranched threads with quadrangular joints, joined