ON THE OCCURRENCE OF RED SNOW IN HERTFORDSHIRE. 251 

of January. On the afternoon of that day, which was the first 
of decided thaw after the recent long and memorable frost, I 
noticed under the upper layer of ice on a large pond in my garden 
sheets of snow of a dark red colour ; and as the position, condition 
of snow, etc., may be of important assistance to future searchers, 
I shall describe them at some length. The pond had been frozen 
for more than a fortnight (on the 15th we were skating on it). 
On the 18th came the violent snowstorm and gale, which covered 
the pond with nearly a foot of drift snow. On the 26th a man 
was employed clearing the snow off the pond, but the lower layer 
(about four inches thick) had apparently partly melted and frozen 
again ; therefore the snow was only cleared away to the surface of 
this frozen layer, which I shall call frozen snow, to distinguish it 
from the true ice underneath. 
On noticing the deep red colour which appeared to be above or 
in the true ice, I dug holes in the frozen snow and found that 
where it rested on the ice it was a deep rose colour ; the water, 
which owing to the rapid thaw quickly filled the holes, became also 
rose-coloured, looking from a short distance like pools of blood. 
I collected a vase of the melting snow, which owing to its small 
quantity and the difference of background looked a lighter pink. 
On rapidly baling the water out of one of the holes, I noticed the 
ice beneath to be full of bright red specks like so many rubies. I 
cut several pieces out, and placed them in a separate vessel for 
examination. The water in the vases (at first a decided pink), 
gradually became paler and paler, and at the end of ten days the 
colour had entirely gone. ; 
Microscopic examination of the melting snow showed frond-like 
patches of green matter, among which were many Zugilena, ap- 
parently Zuglena acus (I could in no case see any flagellum). 
Round green cells, which I took to be the resting form of the 
same L£uglena, and a very great number of yeast-like bodies, 
although they appeared in the microscope to be hyaline, were in 
my opinion the cause of the red colour. These bodies I take to be 
the “ globules” of Meyen. As far as I could see, then and since, 
there was no Protococcus, or to speak more exactly, no body Te- 
sembling Profoecoccus which might not have been some stage in the 
life of the Zuglena. 
I sent three specimens of the melted snow to Mr. Saville Kent, 
the talented author of ‘A Manual of the Infusoria,’ one taken 
from the bottom of my vase with a good deal of sediment, one 
taken from the surface, and the third with the sediment from the 
vase containing the pieces of solid ice, which you will remember 
I spoke of as being full of bright red specks. Mr. Kent tells 
me that the contents of the three phials are identical; that the 
green frond-like masses are decaying masses of Zug/ene, probably 
