THE PLANTS OF THE SEA. 45 
spread about in every direction, always moving with the point or 
rostro foremost. Their movements are lively and curious; some- 
times they abruptly stop, at other times they are seen twisting 
round on their longest axes with great rapidity. If the vase which 
contains them is placed near a window they always make their 
way towards the light. After they have thus been kicking about 
for hours or days, according to the species, the zoospores (fig. Z) 
DEVELOPMENT OF THE ZOOSPORE AND THE FORMATION OF THE YOUNG PLANT, 
(Haligenia bulbosa.) 
fix themselves by their rostro by means of a mucilaginous secretion ; 
their bodies become round, the threads or hairs disappear, they 
either decompose or drop off. At the same time the opposite 
extremity grows thick and lengthens into a tube; in a short time 
secretions appear in this tube, and often the growth is so rapid that 
in a few days the young frond can be distinguished (fig. 11). 
The spore is a little round body filled with an olive-green fluid, 
and which receives from the cz/ia the property of reproducing an 
individual like itself. It is contained in a bag (sporange), which is 
