34 THE WORLD BENEATH THE WAVES 



Foraminifera, yet some of their shells are almost 

 always present in Globigerina and other ooze, and in 

 certain corners of the ocean they are sufficiently 

 numerous to form an almost pure siliceous deposit 

 known as Radiolarian ooze. For reasons that will 

 presently appear Radiolarian ooze is met with only at 

 great depths. 



But the animalcules, and especially the Foramini- 

 fera, whose mortal remains collect to form these 

 calcareous and siliceous oozes, are only found in 

 profusion in oceanic waters of a certain necessary 

 warmth. In the colder waters of the higher latitudes 

 they are not numerous enough to give a dominating 

 character to the sediment that subsides to the bottom 

 of the open ocean. 



Now, amid the teeming life of the ocean there are 

 to be found in abundance certain microscopic plants 

 of the lowliest kind. We must call them plants, 

 because they belong to the vegetable kingdom, but 

 they are not in the least like any plants that are 

 visible to the naked eye. Not only do they swarm 

 throughout the sea, but they are also universally 

 diffijsed in fresh waters, and, in short, wherever there 

 is moisture. These humble microscopic plants" are 

 known as Diatoms, and in the scheme of Nature 

 they stand and wait at the bottom of the class to 

 which the seaweeds and moulds belong, being, in fact, 

 rather nearly related to the Bacteria which have 



