red (some 30 or 40 miles from our camp). He collected some, but abandoned his specimens while saving his life after being carried away on a floe. In a lake close by was our now familiar red rotifer, and he suspected it caused the red snow. Certainly it could do so, if the water swarming with rotifers were blown out over the snow during a gale; they would not be killed by the cold. I find that Agassiz's red snow from the Alps contained red rotifers, probably the same kind." Lagerheim also reported finding rotifers in red snow in Nicaragua. It is quite clear, however, that it does not occur so frequently in the south as it does in the north, probably mainly owing to the higher summer temperatures that occur in the north. The red snow alga is not confined to ice and snow, and I do not consider that ice and snow is its chief habitat. Mr. George Murray, late of the British Museum, told me that he had known of this alga in the cistern of a London house. If one examines the dried-up shallow ponds and pools scattered all over Arctic lands in the late summer, when their water supply fails owing to lack of melting snow, one often finds the whole bottom of such ponds covered with a dark reddish-brown scum, which dries up into a sort of skin, covering all the ground and wrapping itself round every stone. On examination this is found to be
