336 



each other in the same individual ; vegetables in the earlier period of their ex- 

 istence, but producing, in the room of sporules or buds, little microscopic ani- 

 malcules, 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 struc- 

 ture ; such as Diatoma flocculosum, tenue, arcuatum, and obliquatum, and Fra- 

 gillaria striatula and pectinalis ; and he believed Conferva stipitata, Biddul- 

 phiana and tseniaeformis 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 ar- 

 ticulations, at first attached by their longest sides, and afterwards separating at 

 their alternate extremities, so as to form a filiform tube. " The filaments," ac- 

 cording 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 extre- 

 mities and dilated in the centre, to become cylindrical and opaque, and, in 

 short, metamorphosed into a moniliform filament, with elliptical or oblong pur- 

 ple joints and colourless articulations." (Vol. vi. 354.) Agardh is of opinion 

 that we have among these rudimentary Alga? not only a distinct passage to the 

 animal but even to the mineral kingdom: for he states that some of his 

 Diatomese 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 observa- 

 tions above quoted are those of naturalists of so high a reputation for accuracy, 

 that they may safely be accepted as certain ; but I do not know what to say of 

 such as the following, by a German botanist of the name of 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 globules contained in 

 the filaments of Zygnema have a life partly vegetable, partly animal, and pro- 

 create similar globules, some of which become animals endowed with motion. 

 See Agardh's Species Mgarum, 2. 48., from which this account is extracted. 

 Certain supposed Confervas, called Bacillarias, are rejected from plants by M. 

 Bory de St. Vincent, and placed in the lowest grade of the animal creation. 

 See Diet. Class. 2. 128. 



Other Algae approach nearly to the structure of Lichens, lose entirely theiv 

 animal properties, and become broad flat expansions, or finely divided vegeta- 

 bles, such as are seen in the ordinary state of Sea-weeds, Fuci, or marine Con- 

 fervae. Of the British species of these, and of their general nature, an excel- 

 lent acconnt has been given by Dr. Greville in his Algce Briiannicce, from 

 which the greater part of the following remarks is extracted. While the first 

 two 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. Neil], this species forms meadows, through which a pinnace with 

 difficulty forces its way. Lessonia fuscescens is described by M. Bory dc^t. 

 Vincent as 25 or 30 feet in length, with a trunk as thick as a man's thigh. But 

 all these, and indeed every other vegetable production, is exceeded in size by 

 the prodigious fronds of Macrocystis pyrifera. " This appears to be the sea- 



