284 THE MARINE BOTANIST. 



where the opinion generally prevails that the spores 

 on their liberation from the main filament, become 

 animalcules. M. Agardh,* in his account of Con- 

 ferveaerea, describes the sporules as being furnished 

 with a little beak, or anterior process, distinguish- 

 able from the body of the seed by its paler colour, 

 and he considered that it was on the vibrations of 

 this beak that the motion depended. More recently, 

 M. Thurett has discovered that the spores of many 

 among the fresh-water species are furnished with cilia 

 which vibrate in the same manner as do the cilia of 

 the Infusorial animalcules. The spores of the Con- 

 ferveae possess two cilia ; on those of Chsetophora 

 they form a circle, and the spores of Vaucheria are 

 completely covered with them. The spores of the 

 majority of grass-green algoe, when examined with 

 high magnifying powers, are now found to be 

 clothed with cilia, and to manifest these seemingly 

 voluntary movements, which cease as soon as the 

 spore reaches a substance on which it can rest 



* See " Manual of British Algae." Introduction, p. 31. 

 + See " Botanique," par M. Adrien de Jussieu, p. 461. 



