Alge.)| THE HIMALAYAN MOUNTAINS, 44] 
207. ALG. 
The Alga, in the extended signification of the term, include not only sea-weeds, 
but also the articulated salt and fresh water Conferve, together with the still less 
highly developed plants, consisting of mere threads or vesicles, or slimy, jelly-like 
plants, described by Bory de St. Vincent. As the last are found in damp and shady 
situations, or even on rocks, which are kept constantly moist, and such plants as that 
called Red Snow, one of the Nostochine, occur not only near the North Pole, but also 
in the Alps; they may be found in the Himalayas, together with some of the fresh 
water Conferve, which are usually found in temperate climates; while of the true 
Fuci, the Lemanias are only found in the fresh water of mountain torrents. 
In the numerous families treated of in this work, we have seen that many of the 
aquatic species, or those delighting in moist situations, have a more extensive distri- 
bution, in consequence of the greater equability of temperature produced by moisture, 
and we might therefore expect many of the same genera and species in the waters of 
the Indian Ocean, as in those of more northern latitudes; but it has been observed by 
Lamouroux and Greville, that Confervas are comparatively rare within the tropics, but 
a few species are found in Dr. Rottler’s Herbarium from the neighbourhood of Tran- 
quebar. 
The Fucacee are much more extensively distributed, as some occur in all latitudes, 
and though the Udvas flourish most in the polar and temperate zones, Sargassum, 
tropic-grape or gulf-weed, floats in immense fields in 40° of latitude. The Dictyotee 
increase in numbers as we approach the equator ; and Hypnea, Cystoseria, Sargassum, 
Zonaria, Spherococcus, Thaumasia, Acanthophora, Tamnophora, Amansia, Caulerpa, 
and Gelidium, of which swallows build the so much prized “ edible bird’s-nests,” 
abound in tropical seas. Few have been described from the Indian Ocean, but several 
are contained in Dr. Rottler’s Herbarium, which the author will take some future 
opportunity of describing. 
_ The lowest types of Alg@ serve probably as food for animalcules, which them- 
selves become the prey of more highly developed animals. Many of the sea-weeds 
are used as food in different countries, and some, as Laver, are even considered 
delicacies at the tables of the rich, whilst others are valued as diet for the sick. Gracil- 
aria lichenoides is esteemed as food in Ceylon; G. tenar is valued by the Chinese 
as the basis of an excellent glue and varnish, and the Gelidium, collected by swallows 
for their nests, gives origin to a very extensive commerce. Some of the sea-weeds are 
employed as manure; others are burnt for the impure carbonate of soda, which they 
yield ; a few are valued as medicinal agents, from containing among their constituents 
the powerful agent Jodine, so much employed in the treatment of scrofula and of goitre. 
It is curious, as stated by Dr. Greville, ‘‘ that the stems of a sea-weed are sold in 
the shops, and chewed by the inhabitants of South America, wherever goitre is 
prevalent, for the same purpose. This remedy is termed by them palo coto (literally 
aL goitre 
