FUCACEJE 



629 



the projection and narrowing of one end into a kind of foot-stalk, 

 by which the oospore attaches itself, its form passing from the 

 globular to the pear-shaped ; a partition is speedily observable in its 

 interior, its single cell being subdivided into two ; and by a con- 

 tinuation of a like process of bipartition, first a filament and then 

 a frondose expansion is produced, which gradually evolves itself 

 into the likeness of the parent plant. 



The whole of this process may be watched without difficulty by 

 obtaining specimens of F. vesiciilostis at the period at which the 

 fructification is shown to be mature by the recent discharge of the 

 contents of the conceptacles in Irltle gelatinous masses outside their 

 orifices ; for if some of the oospheres which have been set free from 

 the olive-green (female) conceptacles be placed in a drop of sea- 

 water in a very shallow cell, and a small quantity of the mass of 



PIG. 471. Antherids and antherozoids of Fucus platijcarpus : A, branching 

 articulated hairs t detached from the walls of the conceptacle, bearing antherids in 

 different stages of development ; B, antherozoids, some of them free, others still 

 included in their antheridial cells. 



antherozoids, set free from the orange-yellow (male) conceptacles, 

 be mingled with the fluid, they will speedily be observed, with the 

 aid of a magnifying power of 200 or 250 diameters, to go through 

 the actions just described ; and the subsequent processes of germi- 

 nation may be watched by means of the ' growing slide.' x The 

 winter months, from December to March, are the most favourable 

 for the observation of these phenomena ; but where Fuel abound, 

 some individuals will usually be found in fructification at almost 

 any period of the year. This process of fertilisation usually takes 

 place on fronds exposed to the air on the wet beach between high- 

 and low- water mark ; and, to assist in it, the comparatively heavy 

 fronds of many Fucacece are buoyed up by air-cavities, which take 

 the form of the well-known ' bladders ' of the ' bladder- wrack ' and 



1 A shallow cell should be used, so as to keep the pressure of the thin glass from 

 the minute bodies beneath, whose movements it will otherwise impede. 



