Sponges 33 



holes and has passed through a labyrinth 

 of canals and chambers formed of soft 

 living flesh. The mass of sponge may 

 be aptly described as an under-water 

 tenement dwelling, and the constant 

 circulation is maintained by each indi- 

 vidual inhabitant lashing the water with 

 a very fine hair or " whip." The strong 

 currents produced may be easily seen if 

 a living sponge is placed in a small 

 aquarium, for the scraps of dust and grit 

 will inevitably be drawn in by the 

 animal. Add a minute quantity of red 

 ink, and the indrawn current will be still 

 more apparent. Here we have digestion 

 in its simplest form. 



Sponges have no weapons, and once 

 they have attained maturity seek no 

 adventure, the quiet life being all they 

 crave for. They attain their maximum 

 development in the abyssal waters of the 

 mid-Atlantic or Southern Pacific pits 

 five miles in depth, where such immense 



c 



