R. n. CROFT — ON UED SNOW IN UERTS. 171 



and other places, led ]\[r. Shuttleworth aud Professor Agassiz *' to 

 eoiielude that the discolouration was due to an immense nuiuber of 

 moving- animalcules of various shapes and sizes, and to globules 

 which were supposed to be the ova of Philodina roseola. 



Professor Meyen f remarks that Euglena mnguinea and Euglena 

 riridis, which greatly resemble Protococcus,\ are the cause of the 

 red and given snow which has been described by Martins, a 

 naturalist, who had accompanied a French expedition to Spitz- 

 bergen. In this case also globules are mentioned. 



From these researches it is evident that it is not proved that red 

 snow is dependent on one form of organic existence, but that many 

 species both of plants aud animals may contribute to its production. 



Having thus briefly noticed all that I can discover about red 

 snow, I will give a short account of some that 1 found on the 28th 

 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 ; aud as the position, condition 

 of snow, etc., may be of important assistance to future searchers, 

 I shall describe them at some lengtb. 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 

 fi'om 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 Eugle7ice, ap- 

 parently Eiiglena acus (I could in no case see any flagellum). 

 Eouud green cells, which I took to be the resting form of the 

 same Euglena, and a very great number of yeast-like bodies, 



* 'Ann. Nat. Hist.,' Aug. 1841. 

 + 'Ann. Nat. Hist.,' Aug. 1848. 



X See Cohn's Memoir " On the Natural History of Profococcus pluvialis''^ iu 

 'Botanical and Physiological Memoirs' (Ray Society, 1853). 



