THE PAGE OF NATURE. 137 



valleys of the great Runjeet, ascending into Nepaul and 

 the lower slopes of the Himalayas. The most singular 

 member of this curious group, however, is the Tricho- 

 desmium erythrceum of Ehrenberg. It occurs in extra- 

 ordinary profusion in the Red Sea, over the surface of 

 which it spreads for many miles, according to the direc- 

 tion of the wind, in the form of a dark-red shining scum. 

 It is composed of little bundles of filaments marked with 

 striae, which have been compared to minute fragments 

 of chopped hay. In certain states of the weather it 

 emits a disagreeable, pungent smell, affecting strongly 

 the mucous membrane, and causing violent sneezing and 

 ophthalmia, thus adding to the list of annoyances which 

 render the passage of the Red Sea peculiarly disagree- 

 able to passengers from the West. The habit of this 

 alga is widely different from that of its congeners, and 

 resembles that of the Sargassurns or Gulf-weeds, which 

 form extensive floating meadows to the west of the 

 Azores, and are supposed to indicate the site of sub- 

 merged lands. The name of the Red Sea greatly puzzled 

 the ancients, and has occasioned in later times a display 

 of much superfluous learning to determine whether it 

 was derived from the colour of the water, the reflection 

 of the red coral sand-banks and the neighbouring moun- 

 tains, or the solar rays struggling through a dense 

 atmosphere. Another conjecture may be hazarded, that 

 it has acquired its denomination from the extreme pre- 

 valence and conspicuousness of this red alga in its 

 waters. 



The filaments of all the species of Oscillatoria are 

 elastic, simple, exceedingly minute, and mathematically 



