433 
hules contained in the filaments of Zygnema have a life partly vegetable, partly 
animal, and procreate similar globules, some of which become animals endowed 
with motion. See Agardh’s Species Algarum, 2. 48., from which this ac- 
count is extracted. Certain supposed Confervse, called Bacillarias, are rejected 
from plants by Bory de St. Vincent, and placed in the lowest grade of the 
anim?d creation. See Diet. Class. 2. 128. 
Other Algse approach nearly to the structure of Lichens, lose entirely 
their animal properties, and become broad fiat expansions, or finely divided 
vegetables, such as are seen in the ordinary state of Sea-weeds, Fuci, or ma- 
rine Confervse. Of the British species of these, and their general nature, an 
excellent account has been given by Greville in his Alga Britannicce, from 
which the greater part of the following remarks are extracted. While the 
two first groups consist of microscopic objects inhabiting obscure places, shady 
paths, or half-immersed surfaces of stones and banks, the more complete Algae 
comprehend species forming subaqueous forests of considerable extent in the 
vast ocean, emulating in their own gigantic dimensions the boundless element 
that enfolds them. Chorda filum, a species common in the North Sea, is fre- 
quently found of the length of 30 or 40 feet. In Scalpa Bay, in Orkney, ac- 
cording to Mr. NeiU, this species forms meadows, through which a pinnace 
with difficulty forces its way. Lessonia fuscescens is described by Bory de 
St. Vincent as 25 or 30 feet in length, with a trunk often as thick as a man’s 
thigh. But all these, and indeed every other vegetable production, is ex- 
ceeded in size by the prodigious fronds of Macrocystis pyrifera. “ This ap- 
pears to be the sea- weed reported by navigators to be from 500 to 1500 feet 
in length : the leaves are long and narrow, and at the base of each is placed 
a vesicle filled with air, without which it would be impossible for the plant to 
support its enormous length in the water ; the stem not being thicker than the 
finger, and the upper branches as slender as common packthread.” 
These remarks may be concluded by a reference to the following works, 
in which further information relating to the animal nature of certain Confervae 
may be found : Nees von Esenheck Die Algen des Sussen Wassers (1814); 
Treviranus in Ann. des Sc. 10. 22. (1817) ; Gruithuisen in Nov. Act. Acad. 
Leopold. Curios. 10.437.; Cams in the same, 11. 491. (1823); Gaillon in 
Ann. Sc. Nat. 1. 309. (1823) ; and >S'cr. Nov. 1. 44. (1834) ; Desmazieres in 
the same, 10. 42. (1825), and 14. 206. (1828) ; Unger in the same, 13. 431. 
(1828) ; Kutzing in the same, Ser. Nov. 2. 129. 217. and 361. (1834) ; Link 
in the same, p. 321., where the authorities to prove that many reputed Zoo- 
phytes are Algae with a calcareous incrustation ; all of which should be care- 
fully consulted by those who wish to form any accurate judgment upon this 
most curious and interesting subject. 
Geography. This has been treated upon carefully by Lamouroux in the 
Annales des Sciences Naturelles, vol. 7, and by Greville in the Alga Britan- 
nica. Algae are most important in the economy of nature for forming the 
commencement of soil by their deposit and decomposition. The basin of the 
ocean is said to be continually rising by the deposit of such plants, particu- 
larly of Conferva chthonoplastes, the closely aggregated slimy fibres of which 
form dense beds. Ed. P. J. 2. 392. The same circumstance occurs in lakes 
and ditches : the bottoms of some of the former, in this country, are no doubt 
increased by the curious production called Conf. aegagropila. To the peculiar 
distribution of phaenogamous plants into certain botanical regions, a fact fami- 
liar to all botanists, there is something analogous in the submersed Flora of 
the ocean. We find latitude, depth, currents, influencing the forms of Algae 
in nearly the same way as latitude, elevation, and station, atfect those plants 
which are more perfect ; and as many of the latter are confined to small ex- 
tent of countrv, so do several of the Algae extend but to short distances in the 
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