210 FIRST FORMS OF VEGETATION. 
of Ehrenberg.. It occurs in extraordinary pro- 
fusion in the Red Sea, over the surface of which it 
spreads for many miles, according to the direction 
of the wind, in the form of a dark-red shining 
scum. It is composed of little bundles of fila- 
ments marked with striz, which have been com- 
pared to minute fragments of chopped hay. In 
certain states of the weather it emits a disagree- 
able, pungent smell, affecting strongly the mucous 
membrane, and causing violent sneezing and oph- 
thalmia, thus adding to the list of annoyances 
which render the passage of the Red Sea pecu- 
liarly disagreeable to passengers from the West. 
The habit of this alga is widely different from 
that of its congeners, and resembles that of the 
Sargassums or Gulf-weeds, which form extensive 
floating meadows to the west of the Azores, and 
are supposed to indicate the site of submerged 
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 mountains, or the solar rays 
struggling through a dense atmosphere. Another 
conjecture may be hazarded, that it has acquired 
its denomination from the extreme prevalence and 
conspicuousness of this red alga in its waters. 
