THE DI8PERSI0X OF SEEDS AND SPORES. 55 



5. The Wind ; 



6. Insects ; 



7. Birds; 



8. Quadrupeds ; 



9. Snails ; 

 10. Man. 



1. Liocomotion. — Many of the lower Cryptogams 

 are free locomotive organisms, moving either by 

 means of amoeboid contractions and expansions of 

 their mass, or by the aid of vibratile cilia. Some 

 of these are locomotive throughout their entire 

 existence ; others possess the power of movement 

 only during one period of their life-history. Of the 

 amoeboid movement we have an example in 

 ^thalium aepticum, the . so-called " flowers of tan." 

 This fungus is one of the Myxomycetes, and consists 

 of a small naked mass of protojjlasm, which is 

 capable of creeping great distances over a moist 

 surface by means of retractile ijrocesses quite 

 similar to the pseudopodia of the amoeba. 



In Protococcus, again, we have a unicellular plant 

 w*hich during one part of its existence leads a 

 locomotive life, and effects progression by means of 

 a couple of fine hairs or cilia. Ciliary motion is also 

 exemplified in Volvox, so well known to students of 

 the microscope. The peculiar and as yet unexplained 

 movements of some Diatoms must also have an 

 important bearing on the distribution of these 

 minute organisms. 



2. Vital Activity of the Germ. — Of more import- 

 ance in relation to our present subject are such 

 ciliated zoospores as we find in Vaucheria, the common 

 tangle {Laminaria), and the green laver (Ulva). In 

 these algse dispersion is effected by the free and spon- 

 taneous movement of motile swarm-spores aided by 

 currents, so that any further provision for the dis- 

 tribution of the species would be superfluous. 



The antherozoids of Ferns move by means of their 

 cilia, and distribute themselves in all directions. In 

 this way, by swarming over the entire surface of the 



