BREAKING OF THE MERES. 
17 
BREAKING OF THE MERES, 
SIMULATED BY AN EXCESSIVE DEVELOPMENT OF 
UROGLENA VOL VOX. 
BY WM. SOUTHALL, F.L.S. 
The interesting phenomena called the “Breaking of the 
Meres” is, I believe, usually explained as resulting from an 
excessive multiplication and growth of various algae; therefore 
I suppose there is no direct comparison between that and the 
occurrence 1 am about to describe, which had an animal origin, 
hut as some of the appearances were to a certain extent similar, 
the parallel between the two naturally suggested itself. 
This apparently sudden and excessive development of one 
of the Infusoria occurred in a pond at Edgbaston, having the 
extent of about a quarter of an acre, rather deep, and nearly 
surrounded by trees ; no stream runs into it, and it is fed by 
springs. It communicates with another pool at a lower level, 
but in dry weather the water does not run over but only 
percolates through the bank. 
I noticed about the middle of May, 1883, that the water 
had assumed a deep vivid green colour, and regret that I did 
not examine it to ascertain the cause. Rather before the end 
of the month the whole of the water became almost suddenly 
of a light reddish brown colour, very opaque, and almost 
exactly like that we see in the gravel pits in this neighbour¬ 
hood after a storm of rain. It had a curious effect amongst the 
green trees, and singularly enough the lower pool was not in the 
least affected, retaining its original colour and transparency. 
A tumblerful of the affected water showed a large population 
of lively swimming bodies that I at first took to be Volvox 
<flobator , but I w T as then unable to determine their proper 
identity. I left home on the 1st of June, and was informed 
that it was some weeks before the water resumed its usual 
appearance. 
This year I looked out anxiously for a reappearance, and 
early in May found the same organisms were easily observed 
in a glass of the water. After a short time, however, they 
entirely disappeared, whether owing to a change of wind or 
temperature I cannot say, but I strained a large quantity of 
water without finding any. After a while the vivid green 
colour again showed itself in large patches, and they returned 
and again became pretty plentiful, but I could not connect 
the green colour in any way with the organisms, as their 
colour was a dull greenish brown. I now found that they 
were not plants, but animals —Uroglena Volvox —one of the 
