BREAKING OF THE MERES. 
5 
“ Mountain, Meadow, and Mere,” suggests that it may be caused 
by the American weed (^Anacharis alsinastruni) , but, unfortunately 
for this opinion, the “ breaking ” was observed long before the 
American weed became naturalised in Britain. The real cause of 
this phenomenon, so far as the Ellesmere Mere is concerned, is the 
rapid growth of a minute Alga {Echinella articulata, Aq.), which, 
multiplying at an astonishing rate, forms a dark green slimy scum 
which floats on the surface of the water. This Alga was figured in 
English Botany, tab. 2,555, so long ago as 1804, but I am not 
aware that any figure has been published of it since then, and that 
fails to give the precise structure. It is strange that Dr. Eaben- 
horst makes no mention of this plant in his “ Flora Europaae 
Algarum,” although our British Manuals give an adequate 
description of the species (vid “ English Flora,” v. V., p. 498 ; 
Harvey’s Manual of British Algse,” p. 187). 
Having been informed by a friend that a large pool at Hawk- 
stone, the seat of the Rt. Hon. Viscount Hill was “ breaking,” I 
obtained, through the kindness of Lord Hill, a bottle of the water 
for examination, and was much surprised to find that the cause of 
the ‘‘ breaking ” in this pool was a totally different species of 
Alga. If I am not mistaken, it is Anabaena circinatis, Rabh., 
“ Flo. Eur. Alg.,” sec. II., p. 183, which is, possibly the same as 
Anabaena flos-aquce, Bory. It consists of moniliform filaments, 
curved in a corkscrew form, composed of nearly spherical cells, 
*005, containing green chlorophyl, with here and there a colourless 
cell, slightly larger than the others. These colourless cells are 
joined to a large oblong ovate cell, *015 x *007 mm., replete with 
a dark green chlorophyl in coarse granules. These large cells drop 
to the bottom of the vessel containing the water, surviving the 
decay of the rest of the filament. The colourless cells probably 
part with their chlorophyl to these larger oblong cells. 
DESCRIPTION OF PLATE, 134. 
Fig. a. — Echinella articulata, nat. size. Filaments, 0‘7 mm. long. 
Fig. h . — Single plant enlarged about 70 times. 
Fig. c. — Filaments more highly magnified, each with a spherical cell at the 
base, ‘OOS-'O! mm., filled with chlorophyl. 
Fig. d. — Spherical cells, with very thin walls filled with minute granules, 
in an active state of motion. These cells soon become empty, and 
the fractured remains of the cell membrane remain. I have only 
seen these cells once. 
Fig. e . — Anabaena circinalis, Rabh., nat. size. 
Fig. /. — Groups of filaments. 
Fig. g . — Single filament, showing large oblong cells, with the two adjacent 
colourless cells. 
