Some Questions which they Suggest. 15 



spores it seems essential that there should be water 

 enough for the swarm spores to live and move about in ; 

 and, in the case of myxies, to enable them also by their 

 movements to join together into a plasmodium. Nothing 

 is known of their reproduction except in water. 



It would at first sight appear that this condition of 

 their reproductive activity cannot be otherwise than in- 

 convenient and restrictive, especially in the case of such 

 myxies as, e.g., the Comatrichas, which often produce their 

 sporangia on the upper sides of wood, or on the tops or 

 sides of wooden posts. .But it is probable that a very little 

 moisture is enough, and that in a shower of rain, or in a 

 morning's dew, they find sufficient water for the swarm 

 spores to live and unite. But we confess that the point 

 seems to us to require further attention. 



Water being the medium in which most of the lowest 

 organisms exist, it is generally thought that the doctrine 

 of evolution involves this that the earth has been peopled 

 by migrations from the water : and the migrations ol 

 amphibious animals from the one element to the other, 

 have been dwelt on as assisting us to understand such 

 migration. In this connection the cases of the myxies 

 and of the mosses, and no doubt of other mainly terrestrial 

 organisms which need water as a necessary condition to 

 fertilization, are worthy of note. One of the most important 

 functions of life still depends on the presence of the original 

 medium of their lives. 



CELL THEOBY. The swarm spore is, as we have said, 

 a bit of naked protoplasm ; so is the plasmodium. Let us 



