432 
at other times very intense green, purple, or yellowish ; these compound fila • 
ments present to the astonished eye the strangest and most different pheno- 
mena, all of which have the plainest characters of animal life, supposing that 
animal life is to be inferred from motions indicating a well-marked power of 
motion. The Arthrodia tribe usually inhabits either fresh or sea- water, and seve- 
ral species are common to both . One of them, but a species referred^to the tribe 
wdth some uncertainty, the Conferva ericetorum, grows on the ground, but in 
places that are very damp, and often inundated ; others among the Oscillating 
species cover the humid surface of rocks or earth, and the interstices in the 
pavement of cities ; some even grow in hot springs of a very high tempera- 
ture. (Ulva thermalis lives in the hot springs of Gastein in a temperature of 
about 117° Fahrenheit. Ed. P. J. 4. 206.) The most remarkable are, 1st. 
The Fragillarias, to which Diatoma and Achnanthes belong ; these, when com- 
bined in the little riband-like threads which are natural to them, have no ap- 
parent action ; but as soon as the separation of the joints takes place, a sort of 
sliding or starting motion may be seen between them. 2dly. The Oscillarias, 
some of which have an oscillatory movement, extremely active and perceptible ; 
and the Ulva labyrinthiformis and Anabaina, which, with all the appearance 
of a plant, has, according to Vauquelin and Chaptal, all the chemical charac- 
ters of an animal. 3dly. The Conjugatse, the filaments of which separate at 
one period, and unite again at another, and finally, by a mode of coupling 
completely animal, resolve themselves into a single and uniform being : and, 
4thly, the Zoocarpese, most extraordinary productions, in which the animal 
and vegetable natures foUow each other in the same indi\ddual ; vegetables 
in the earlier period of their existence, but producing, in the room of sporules 
or buds, little microscopic animalcules, which become filamentous vegetables 
after a certain length of time. GreviUe, in his Flora Edinensis, adopted an 
opinion of Fleming and others, that many of the species referred to this group 
possess an animal structure ; such as Diatoma flocculosum, tenue, arcuatum, 
and obliquatum, and Fragillaria striatula and pectinalis ; and he believed Con- 
ferva stipitata, Biddulphiana and tseniseformis of Eng. Bot., together with the 
whole genus Echinella, to be equally dubious. But he altered this opinion 
after two or three years, if we are to judge from his Cryptogamic Flora, in 
which are beautiful figures of some of the very beings the animal nature of 
which is so much to be suspected. For example, Diatoma tenue, a little Con- 
fervoid plant with parallelogramic articulations, at first attached by their 
longest sides, and afterwards separating at their alternate extremities, so as to 
form a filiform tube. “ The filaments,” according to an interesting observation 
of the Rev. Mr. Berkley, “ at a certain period seem to lose the squareness of 
their figure, to be attenuated at the extremities and dilated in the centre, to 
become cylindrical and opaque, and in short, metamorphosed into a monili- 
form filament, with elliptical or oblong purple joints and colourless articula- 
tions.” (Vol. vi. 354.) Agardh is of opinion that we have among these 
rudimentary Algae not only a distinct passage to the animal, but even to the 
mineral kingdom : for he states that some of his Diatomeae include vegetable 
crystals bounded by right lines, collected into a crystalliform body, and with 
no other difference from minerals than that the individuals have the power of 
again separating. System, xiii. The observations above quoted are those of 
naturalists of so high a reputation for accuracy,^ that they may safely he ac- 
cepted as certain ; but I do not know what to say of such as the following, by 
Meyen, unless that they require to be verified by others, especially because 
those who have sought for the phenomena he mentions have-not succeeded in 
finding them. This writer states that he has seen, very often, a spontaneous 
motion in Zygnema nitidum ; and its filaments contract from the length of 10 
inches to that of 4-6 lines ; that the Oscillatorias move in a circle ; that the glo- 
