zoological museum, tring. 
53 
Case VI. 
In this case the Amphibians will be exhibited. At 
present we may here admire an enormous Wasps’ 
nest, found at Watford, surpassing in size all others 
known to us. In this case, however, the Fishes 
commence, and we are at once attracted by some 
Sharks {Selachoidei), and especially by the Spinous 
Shark {^Echinorhinus spinosus), whose body is 
covered with round tubercles — a ground-shark, but 
very rarely captured in British waters. A re- 
markable form is also the Hammerhead {Zygaena 
malleus). 
The following case contains the 
Rays (Batoidei). 
Of these the most interesting are the Torpedo- 
Rays, also called “Cramp-fish” or “Numb-fish.” 
One of these. Torpedo hebetans, is not uncommon 
in our deeper waters, and it has, like its congeners, 
the power of giving electric shocks of considerable 
strength — a power which ceases with life. The 
electric organ consists of a battery of between four 
and five hundred hexagonal prisms of cells con- 
taining a gelatinous substance. 
We now pass through the open doorway and 
are in the 
