1 88 THE SWAN AND HER CREW. 



a portiDn of the outer membrane begins to swell, and a tongue- 

 shaped projection is formed, which becomes a sort of root. 

 The one chamber of the spore gradually subdivides, and be- 

 comes two, four, and so on, until for the simple spore we have 

 a tiny leaf-like expansion, now known as the prothallium, or 

 representative of a leaf. 



Further than this the spore alone has no power to go, and 

 the prothallium is not truly the germ of the future plant. True 

 germs, needing fertilization, are produced upon it, and also the 

 means whereby they can be fertilized. These can be dis- 

 tinguished only by use of the higher microscopic powers. ]f 

 a portion of the prothallium is examined, it will be found 

 studded with little bladders, containing round semi-transparent 

 bodies of a greenish hue. 



There may also be seen, though in fewer numbers, pellucid 

 cells of an entirely different character, consisting apparently 

 only of a fine membrane, forming an angular chamber, shaped 

 in some instances like a lantern of extreme delicacy and 

 elegance. From the top of this chamber a funnel-like shaft 

 descends to a little germ which is situated at the bottom. 

 This germ is the real original of the future plant, and the round 

 bodies in their little cells, just before described, are the means 

 whereby it is to be fertilized and receive energy to develope 

 into the perfect fern. 



But how can the needful contact between the germs and 

 the fertilizing bodies be brought about? Observation and 

 experiment supply a strange answer to this question. 



The round bodies in the tiny bladders acquire a spiral or 

 shell-like form when they become mature. If a drop of water 

 is then placed in contact with the bladders, their contents will 

 suddenly escape, retaining for a moment the coiled appearance, 

 but quickly lengthening and partially unrolling. 



By means of hairs with which they are furnished, and which 

 at once commence a ceaseless jerking motion, they forthwith 

 launch out into the water, and conduct themselves therein 

 more like creatures endowed with conscious life than mere 

 organs of a settled and sedate member of the vegetable 

 kingdom. 



These bodies, drawing near the germ-cells in the course of 

 their travels through the, to them, vast ocean of the water-drop, 

 have been seen arrested in their progress and passing down the 



