36 



GUIDE TO THE CORAL GALLERY, 



High Cases 

 I. II. and 

 Table Case 1. 



of commercial sponge, has a flat disk-shaped body with numerous 

 oscules on the upper surface. 



The Levant Lappet, which is a variety of Sjiongia officinalis, 

 forms huge thiu flaps like an elephant's ear ; occasionally the edges 

 of the flap unite to form a capacious funnel-shaped cup. 



The above three species {S. officinalis, S. zimocca, and H. equina) 

 include numerous varieties and variations which need not be further 

 alluded to here. 



Commercial Sponges flourish in sub-tropical and tropical waters in 

 depths of 2 to 100 fathoms, the world's supply coming almost entirely 



Fig. 19. 



Section of Hippospongia equina, the Common Bath Sponge. (Natural size.) 



from the West Indies and eastern half of the Mediterranean. In the 

 latter region they are collected by 'divers, who descend naked or in 

 diving-dresses, or by men who hook up specimens by means of a 

 long harpoon ; dredges are employed in deeper waters. In the West 

 Indies (Florida, Bahamas, &c.) the hooking method is employed, a 

 bucket with a pane of glass in the bottom being used as a submarine 

 spy-glass to do away with the effect of the surface ripples. 



Sponges are prepared for market by macerating them in sea- 

 water in staked enclosures ; after a few days the skin and flesh rot 

 off, and can then be beaten out ; the skeletons are hung up in 

 strings to dry and bleach in the air and sun. 



