A GUIDE TO THE SPONGES 249 



and Sheep's-wool Sponges (Hippospongia meandriformis D. & M. 

 and H. gossypina Hyatt). These are the best of American 

 bath-sponges. (Figs. 27 and 29)^ 



The third grade, the Zimocca Sponge {Euspongia zimocca 

 F. E. Schulze), is not as soft as the others, and corresponds 

 to the Florida Yellow Sponge or "Hardhead." (Figs. 26 and 

 28). 



The Grass Sponge {Euspongia graminea Hyatt. Fig. 30) is 

 the poorest grade of American sponge and is of little commercial 

 value. 



Sponges grow attached to rocks and other objects at the sea- 

 bottom. They are obtained in shallow water by means of long 

 iron hooks, which, however, often damage the sponges by tearing 

 them. The most perfect specimens as well as the largest are 

 obtained at greater depths by divers. The Dalmatian fishermen 

 are very skilful at this. The diver is stripped and has a small 

 rope attached to his waist weighted with a slab of stone. He 

 seizes the stone in his hands and dives to the bottom. A skilful 

 diver can remain under water for two to three minutes, during 

 which time he quickly gathers whatever sponges he can find and 

 places them in a net attached to his neck. He is then quickly 

 drawn to the surface. Diving by this method is confined to the 

 summer season, as the winters are too cold for such work. The 

 Greek divers use a water-glass to locate their sponges. This is 

 a metal cylinder somewhat longer than a band-box, open at the 

 top and closed at the bottom by a plate of glass. By holding 

 the glass-covered end below water, a person looking through it 

 can easily see the bottom at a depth of 180 feet. The divers 

 work in regulation diving-suits supplied with air from above. 

 Under these circumstances they can remain below for a length of 

 time varying from an hour to a few minutes, depending on the 

 depth at which they are working. The best sponges are obtained 

 in this way, as they are more perfect and of larger size in deep 

 water, and can be removed from the rocks with greater care. 



Dredging is also practised off the coast of Asia Minor. 



Sponges are prepared for the market by first exposing them 

 to the air imtil the animal matter begins to decay. They are 

 then washed, either by beating, by treading them with the feet 



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