64 WONDERS OF THE DEEP 



What is a sponge ? For a great many years this 

 question puzzled scientists, and for a long time the 

 sponge was regarded as being a form of plant life. 

 There appeared to be good reasons for classifying it 

 with the vegetable world, because, in form, the sponge 

 is in many ways like a plant, and also because it is 

 fixed to a particular spot just as an ordinary plant is 

 kept in a certain position in the soil by means of the 

 root. 



It was not until the year 1829 that a scientist, 

 named Grant, carried out a number of careful obser- 

 vations of the habits of these remarkable creatures, 

 and discovered their method of feeding. His investi- 

 gations of sponge life led him to assert that sponges, 

 although fixed to one spot, really belong to the animal 

 and not to the vegetable kingdom. Since then, further 

 scientific observations have been made and their struc- 

 ture has been closely examined, so that nowadays 

 scientists are fully agreed that sponges must be classi- 

 fied with the lower forms of animal life. 



One end of the sponge is fixed to the bed of the 

 sea, while the other end is open. This opening is 

 known as the osculum. The walls of the sponge are 

 penetrated by innumerable small canals. Currents of 

 water, passing through the smaller pores and out at 

 the larger openings, contain a variety of still lower 

 forms of life on which the sponge makes its meal. 



In its natural state, on the floor of the sea or ocean, 

 the sponge is a living thing, but the sponge that is 

 sold as a commercial commodity is but the framework 

 or skeleton of the original living creature. When 



