200 



THE MICROSCOPE AND ITS LESSONS. 



are composed of flint. They are to the sponge what the 

 earthy deposit in the bony structure is to more perfect 

 animals, and they are amongst the earliest developed of 

 the organs of the sponge. They are the instruments of 

 defence as well as the organs of prehension ; and what a 

 formidable array of daggers, lances, spears, and harpoons 

 do they present ! Woe be to the tiny mite that comes too 

 near these flinty weapons of attack and defence ! 



Do you see how God has provided this humble crea- 

 ture, a soft gelatinous mass only of living matter, with 

 the most effectual means of self-protection ? Then, too, as 

 between the larger spicula the smaller tribes of animals 

 so abundant in the sea would readily insinuate them- 

 selves, there is frequently a secondary series of defensive 

 weapons all formed, mind, of flint, a perfect armoury, 

 of short, finer-pointed spikes, thus rendering the progress 



of the smaller enemies 



extremely difficult, if 

 not impossible. 



Now just look at 

 this : it is the weapon 

 of defence as well as 

 the organ of protec- 

 tion, used by a kind 

 of marine slug in the 

 same manner as we of 

 the upper class use our 

 hands. This humble 

 denizen of the seas is 

 provided with the 

 most wonderful coat 

 of armour that has ever been seen. The Synapta, from 

 which these spines were taken, is furnished with numerous 

 anchor-shaped weapons, which articulate in a beautifully 



Anchors and plates of Synapta, detached. 

 Drawn from nature. 



