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 Spongia officinalis, 

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

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



The above three species {8. 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 sul^marine 

 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. 



