40 MOSSES AND LIVERWORTS 



made, by the help of which the fruit is eventually 

 formed. These spiral bodies are so diminutive 

 that they only become visible at all when highly 

 magnified; they have this wonderful faculty, 

 that when they are freed from the surrounding 

 cell-walls by which they are at first enclosed 

 and this takes place soon after their escape 

 they are able to move about in water, by the 

 help of two very delicate hairs, or cilia ; indeed, 

 when seen for the first time under the microscope 

 they might easily be mistaken for microscopic 

 animals, so decided is their motion. We can now 

 understand how it is that water plays so im- 

 portant a part in this matter of fertilisation, for 

 by its means one of these tiny spiral bodies can 

 find its way to the head of one of the ripe fruit- 

 bearing organs ; it can then pass down the narrow 

 passage which, as we have seen, has been formed 

 down the neck, and so enter the cavity in the 

 swollen base, and it will there fertilise that 

 special cell to which I have alluded above. 

 Sometimes we may be so fortunate as to examine 

 a specimen tinder the microscope just when the 

 fertilising organs are ready to burst, and a slight 

 pressure on the thin cover-glass will then suffice 

 to bring this about, and we may see the cloud 

 of cells escape under our very eyes. Plate III. 

 fig. 9 is a drawing of a group of the reproductive 

 organs of one of the Thread-mosses (JBryum 

 intermedium}, and shows one of the cucumber- 



