186 CHLOROSPERME^E 



grass-green or blue-green colour of the frond. A very few 

 are tinged with lurid purple, and a few others with brown. 

 A simplicity of structure, and fructification dispersed through 

 the whole colouring substance of the frond, not confined to 

 distinct conceptacles, combined with the herbaceous green 

 colour just spoken of, are the marks by which we recognize 

 a Chlorospermatous Alga. When we examine these plants 

 a little more closely, with high magnifying powers, we ob- 

 serve that the spores of a large number of them, perhaps of 

 all, are, just at the time of their emission by the parent plant, 

 clothed with vibratile cilia, and endowed with a peculiar mo- 

 tion, strongly resembling the voluntary motion of animalcules. 

 The little spore, whilst contained within the mother cell, 

 commences life by knocking continually against the walls of 

 the enclosure until it has burst through them into the sur- 

 rounding water ; and then, with many gyrations and rapid 

 changes of place, it swims about by means of the cilia with 

 which it is furnished, until it reaches a substance on which it 

 can rest and attach itself. Once attached, its seemingly vo- 

 luntary motions cease. The cilia are absorbed or perish. 

 The semblance of animal life is laid aside, and the vegetable 

 cellule commences the growth natural to its kind, and finally 

 becomes a plant like its parent. Some observers claim for 

 it an animal life during the season of its ciliary movements, 

 and certainly there is a very striking similarity between these 

 movements and the movements which w T e observe in the ova 

 of many of the lower animals, particularly of the class Radi- 

 ata. But that it is a resemblance, a connexion of analogy 

 only, I can scarcely doubt. All must admit that the two 

 great kingdoms of animated nature animals and plants 

 (for that plants are endowed with a life analogous to that of 

 animals can no longer be doubted) approach each other, 

 through the lower members of either kingdom, and seem al- 

 most conterminous. In the spores of these Algae we find 

 one point of seeming contact, but this is laid aside on the 

 commencement of the development of the frond. In some 

 of this sub-class, as in the Diatomaceee and Oscillatoriete, 

 the motion is not always confined to the spore, but the fully 

 formed frond enjoys this singular power in a greater or less 

 degree through the whole of its life-time. And, if you will 

 have it so, the movements of the sensitive plant and of He- 

 dysarum gyrans are further instances, taken from among the 

 higher vegetables, of a movement, to all appearance sponta- 

 neous, perhaps voluntary. And if animals be distinguished 



