ALG.«. 149 



granules, which make the surface to appear reticu- 

 lated. When mature they burst, and the internal 

 granules escape, to the number of six or eight or 

 more, and the membrane only of the globule is left 

 behind, buoyant and colourless. The granules are 

 globose, and escape from the globules one by one, 

 adhering together, though I never could observe the 

 least voluntary motion among any of these bodies." 



In the year 1878, Brun noticed on the sacred 

 mountain near the city of Ouessin, in Morocco, a 

 so-called "rain of blood," which he found to result 

 from a quantity of minute shining flakes, which 

 adhered closely to the rocks and presented an ex- 

 traordinary resemblance to drops of blood. These 

 were found to be a young and undeveloped condition 

 of Chlamydococcns, mixed with organic remains and 

 fine sand. He suggested that they had been brought 

 by a strong south-west wind from the Sahara, where 

 the Chlamydococcus is assumed to be extremely abun- 

 dant. There is a record extant of the occurrence of 

 red snow in Hertfordshire, in 1881, but the account 

 there given is rather mixed, and even the inference 

 that some condition of Eiiglcena caused the red appear- 

 ance serves in no way to elucidate the mystery.^ 



Martius, who twice accompanied French expedi- 

 tions to Spitzbergen, writes of a green field of snow 

 which was seen on the coast of Spitzbergen, in July, 

 1838. The surface of the snow was white, but a iQ.\^ 

 centimetres below it was deeply coloured, as if it 

 had been sprinkled with a decoction of spinach. In 



* M. C. Cooke, "Introduction to Fresh Water Algse," pp. 170-172. 

 (1890.) 



