THE SPONGES OF GUERNSEY. 



BY ERIC W. SHARP. 



FEW people are unacquainted with that common object of the 

 bath-room — the sponge. Many have read of its origin and the 

 methods employed in gathering it from its ocean bed. To 

 them appears a picture of a small boat rocked on the wavelets 

 of a crystal tropic sea, manned by dusky men who spend half 

 their time in diving to the bottom, there to tear off the lumps of 

 slimy sponge that festoon the rocks. The fact that sponges live 

 on our own coasts and in huge quantities is, however, frequently 

 overlooked. The reason is not far to seek, for our local repre- 

 sentatives are far different in form and texture to the ones that 

 produce the sponge of commerce. Instead of being large, 

 upstanding masses they are in general low and often unsightly 

 growths covering rocks and seaweeds in the littoral and deeper 

 offshore water. 



Let us take a common bathroom sponge and examine it. We 

 find it to be a fibrous and extremely porous mass, perforated by 

 holes, large and small. What we are handling is, however, 

 merely the dead skeleton, which in life was the support and 

 home of the countless unicellular animals that compose the 

 living sponge. If this same specimen had been examined 

 directly it came out of the sea it would have been noticed that 

 the whole was covered with a slimy material, which is the real 

 sponge flesh or sarcode. The fisherman spreads his catch out in 

 the fierce sun and there the flesh decomposes and falls away. 

 The remaining skeletons are cleaned and sorted and sent off to 

 the market. 



Thus we have discovered that a sponge consists of a skeleton 

 and living matter. Let us delve a little deeper into its structure 

 and life historj^ for it is worthy of attention. 



Starting with the skeleton, we find that four great groups 

 exist. One, the Myxospongia, are jelly-like and have prac- 

 tically no skeletal support. The second, Calcispongia, have 

 innumerable spicules of lime interwoven to form a sheleton. 

 The third, or Siiicispongia, substitute flint for lime, while in the 

 Ceratospongia the support is fibrous. Our local sponges belong 

 mainly to the Calcispongia and Siiicispongia, the latter pre- 



