56 
THE VOYAGE OF THE VEGA. 
[chap. 
On a closer examination it appeared that this light-pheno¬ 
menon proceeded from a minute crustacean, which according to 
the determination of Prof. W. Lilljeborg belongs to the species 
Metridia armada, A. Boeck, and whose proper element appears 
to be snow-sludge drenched with salt water cooled considerably 
under 0° C. First when the temperature sinks below — 10° 
does the power of this small animal to emit light appear to cease. 
But as the element in which they live, the surface of the snow 
Metridia armata, A. Boeck. 
1. A male magnified twelve times. 2. A foot of the second pair. 
nearest the beach, is in the course of the winter innumerable 
times cooled twenty degrees more, it appears improbable that 
these minute animals suffer any harm by being exposed to a cold 
of from - 20° to - 30°, a very remarkable circumstance, as they 
certainly do not possess in their organism any means of raising 
the internal animal heat in any noteworthy degree above the 
temperature of the surrounding medium. 
