6 FAIBY LAND AMONG THE SPONGES 



When the currents are fairly 

 established, the magnifying glass 

 will exhibit a wonderful phase of 

 animal life. 



The whole of the surface, of 

 the sponge is covered with little 

 prominences, having at the tip 

 of each a tolerably large aper- 

 ture. Through this hole the 

 coloured water pours outwards, 

 causing the currents which have 

 made themselves visible. 



But how did these coloured 

 particles, which rush out with 

 such force, get into the sponge 

 at all ? A more powerful lens 

 will solve the problem. The 

 whole of the surface is studded 

 with innumerable little holes, 

 piercing through the gelatinous 

 membrane and admitting the 

 water into the interior of the 

 sponge. A section of the sponge 

 will show that these little holes 

 lead int6 canals which travel in 

 every direction through the sub- 

 stance of the sponge, and finally 

 lead to the larger apertures 

 through which the water is ejected. 

 Fig. 1. GLASS-ROPE SPOXGE (Hyalonema 

 Lausitanicum). Half real size. 



