340 



are called Confervae, or, as M. Bory styles them, Arthrodieae/ These, which 

 comprehend true Confervse, Oscillatorias, and many Diatomese, .are thus 

 spoken of by the acute botanist last mentioned: — The general character of 

 Arthrodiese consists in filaments, generally simple, and formed of two tubes, 

 of which one, which is exterior and transparent, offers no trace' of organi- 

 sation to the most powerful eye, so that it might be called" a tiibe of glass, 

 contains an inner articulated filament filled with colouring matter, often 

 almost imperceptible, but at other times very intense green, purple, or 

 yellowish ; these compound filaments present to the astonished eye the 

 strangest and most different phenomena, 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 volition. The Arthrodia tribe 

 usually inhabit either fresh or sea-water, and several are common to both. 

 One of them, but a species referred to the tribe with 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 temperature. (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 

 Diatoms and Achnanthes belong ; these, when combined in the little riband- 

 like threads which are natural to them, have no apparent 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 characters 

 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; an'd, 

 4thly, the Zoocarpese, most extraordinary productions, in which the animal 

 and .vegetable nature follow each other in the same individual ; 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. Dr. Greville, in his Flora .Edinensis, 

 adopted an opinion of Dr. 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 Conferva 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 Confervoid plant 

 with parallelogramic articulations, at first attached by their longest sides, 

 and afterwards separating at their alternate extremities, so as to form a fili- 

 form 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 be- 

 come cylindrical and opaque, and, in short, metamorphosed into a moniliform 

 filament, with, elliptical or oblong purple joints and colourless articulations." 

 (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 Diatomeoe include vegetable cfystals 



