THALLOGENS. 239 
backward and forward motion during the next half hour, presenting 
8 most singular spectacle to the observer. Sometimes a partition is 
formed in advance of the mucous bed, which prevents the ulterior 
action of the locomotive corpuscles from exercising themselves 
upon it. These movements will endure for yet another hour ; but 
they become gradually slower and slower, ceasing entirely at the 
end of a few hours. 
It is after the introduction of the antherozoids into the sporange 
that a large cell or spore forms itself in the interior of the sporange, 
which completely fills it. At first greenish, oS 
this cellule becomes paler by degrees, and A 
presents in its interior many larger bodies 
of a sober brown (Fig. 312). Sometimes 
it is isolated from the tube in consequence 
of the membrane of the sporange begin- 
ning to decompose. At a certain time, 
that is, in about three months, this spore 
begins torecover its green colour; it becomes "is: #12-_ Formation of Spores. 
elongated slowly, and soon assumes the form of a young tube of 
Vaucheria, and in a short time it is a perfect resemblance of the 
mother plant (Figs. 313 and 314). 
Figs. 313, 314. Spores of Vaucheria germinating. 
ae is the double and singular mode of fecundation in the 
@ucheria, It was foreseen by .Vaucher, who recognised the 
utst, and suspected the importance of the cornicles ; but we are 
indebted to Von Pringsheim, an able German anatomist, for the 
“omplete and circumstantial relation which is here presented. The 
ny vesiculosus (see Fig. 315) is the commonest and best known of 
_ @ the Marine Algz. It is found on all the shores of Europe, and 
