STRUCTURE.] SPORULES OF FUCU&. 129 



we shall describe the appearances found in Fucus serratus, 

 vesiculosus, and the other varieties referred to these species. 

 The signs of division marked by furrows on the olive-coloured 

 matter of the spore become more and more distinct, until 

 they look like true partitions ; the spore is then found to be 

 divided into eight masses which gradually separate from 

 each other, and then form as many smooth spherical sporules. 

 The epispore is soon after destroyed, and each sporule begins 

 to germinate. 



"The germination of Fucus serratus takes place as follows: 

 About twenty-four hours -after the division just described, 

 a very small tumour appears on the surface of the sporule. 

 At the end of forty-eight hours this tumour is elongated into 

 a cylindrical tube filled with a quantity of olive yellow 

 granules : a transverse partition is formed in the sporule 

 which is thus divided into two hemispheres. After three 

 days, another partition is formed at the entrance of the tube ; 

 the colour of the sporules remains unaltered. By the fourth 

 day a new partition divides the mass into four equal parts, 

 in each of which a sort of denser nucleus is observed. By 

 the fifth day, the divisions are multiplied so as to part the 

 sporule into six portions. While these changes are taking 

 place the tube continues to grow, but without forming any 

 partitions. These observations, it will be seen, differ from 

 those of M. Agardh, who, by the bye, has clearly mistaken 

 the germination of a sporule for that of a spore itself. (Ann. 

 des Sc. Nat., torn. vi. p. 209. tab. 15.) 



" The spore of Fucus nodosus is divided into four sporules 

 as has been observed by M. Crouan (Ann. des Sc. Nat., 3d 

 series, torn. ii. p. 366. tab. 11). This plant is also peculiar in 

 another way ; it is sometimes dio3cious, at others monoecious. 

 Hence it is that it is sometimes found covered with male or 

 female conceptacles only ; whilst at others the two sexes are 

 found on the same stem, but borne on distinct receptacles. 



" Fucus canaliculatus and F. tuberculatus are both herma- 

 phrodite. In the former, the antheridia are distinguished 

 by their hyaline colour, and the corpuscles within them have 

 not the red granule which was found in all the other Fuci. 

 The spore, at the moment of its liberation, is marked by two 



VOL. II. K 



