XXX INTRODUCTION. 



probably owing to tlieir confined situation ; and as I was 

 six or eight miles from the sea, and had not the opportunity 

 of placing the pebbles in some of those pools which are 

 left by the sea at low water, I discontinued the experiment." 

 It is much to be regretted that Mr. Sfackhouse, in con- 

 ducting the above experiment, did not make more use of 

 the microscope. We are not told how the membrane pro- 

 ceeded from the spores, nor whether the sprouts arose from 

 each single spore, or from several associated. 



More recently, on the continent, M. J. G. Ayardli, son 

 of the celebrated Swedish algologist and worthy successor 

 to his chair, has made more minute observations on the 

 germination both of spores and of tetraspores, of several 

 species, and has published magnified figures of the young 

 plants in various stages of development. His memoir on 

 this subject will be found in the ' Annates des Sciences 

 Naturelles^ for October, 1836; and I shall here extract 

 some of its more interesting matter. According to him, 

 whatever may have been the shape of the spore before it 

 issued from the capsule, it soon acquires a spherical form, 

 and is then undistinguishable from the tetraspores of the 

 same species, which likewise germinates in the same manner. 

 In his figures, for I regret to say he has not detailed the 

 whole process, nor given an account of his method of pro- 

 ceeding with the plants, he has represented the first effort 

 of germination as showing itself by the spore acquiring an 

 oval form ; a minute papilla then issues from one end, 

 which elongates and becomes the root; the upper end 

 likewise pushes in an opposite direction, gradually elon- 

 gating, and increasing in diameter by the production of new 

 cells, till at length it acquires the character of the species. 

 He has figured the germination of the spores and tetraspores 

 of Ceramimn ruhrum and Laurencia pinnatijida, and of 

 the spores of Fucus vesiculosus ; to all which the above 



