60 
THE BREAKING OF THE SHROPSHIRE MERES. 
“ Botanist’s Guide,”* (p. 310) records the occurrence of a 
Rivularia in a locli, near Aberdeen, which gave the water a peculiar 
appearance, in these words :—“ Numerous minute bodies, with a 
spherical outline, and varying in size from l-24th to l-12tli of an 
inch in diameter, were seen floating at different depths, and giving 
the water a peculiar appearance. In some places they were very 
densely congregated, especially in small creeks at the edge of the 
loch. A quantity was collected by filtration through a piece of 
cloth, and, on examination by the microscope there could be no 
doubt that the production was of a vegetable nature, and a species 
of Rivularia , one, however, unknown to me, and not agreeing with 
the description of any species in works to which I had access. 
Specimens were sent to the Rev. M. J. Berkeley ; he informed me 
that the plant belonged to the genus mentioned, and stated it to be 
Rivularia echinata, Eng. Bot. Along with it, but in very small 
quantity, I found another plant, Trichormus flos-aqua , Bory.” 
Dr. Drummond wrote an account of an alga,f which formed the 
colouring matter of a lake in the county of Monaghan, Ireland, 
called Glaslougli, which signifies, in the Irish language, “the 
green lake,” an appellation given to it from time immemorial on 
account of the hue of its waters, which exhibit a green tinge 
equal to, or exceeding in intensity, that of the sea, though it is not at 
all times equally striking. Dr. Drummond writes as follows : “ The 
opposite banks of the lake, which are high but not rocky, are 
thickly clothed with a wood of noble trees, and on my first seeing 
this beautiful sheet of water I was inclined to suspect that its green 
colour might arise simply from the reflection of the rich foliage on 
its surface. On further enquiry, however, I ascertained that the 
colour resided in the water itself, and was owing to what I believe 
is an undescribed Oscillatoria. When a little of the water is lifted 
in the hand it seems perfectly transparent, and it appears equally 
clear at the edges of the lake, in a depth of not more than a few 
* “ Botanist’s Guide to the Counties of Aberdeen, Banff, and Kincardine,” 
G. Dickie, 1860. 
f On a new Oscillatoria , the colouring substance of Glaslough Lake, 
Ireland, by James L. Drummond, Professor of Anatomy in the Boyal Belfast 
Institution .—Annals of Natural History, 1838, Yol. I., p. 1. 
March, 1893. 
