THE MAILED WARRIORS OF THE SEA. 161 
bearing three branches, move gently to and fro in 
the water. Why do they do this ? Because in their 
last joint where they touch the head, is a little bag 
beset with hair, and having in it a thick fluid and 
some tiny particles of sand, and this is the ear of the 
prawn from which a nerve passes to the main nerve- 
mass in his head ; so that as he moves the antennules 
in the water, he is, as it were, listening without ceasing 
to all sounds that may pass through it. Just above 
these hearing organs a pair of gleaming eyes stand 
out upon short stalks, and if you examine these 
under the microscope, you will see that they are 
composed of a number of six-sided facets arranged 
in a hemisphere, so that the prawn can keep a sharp 
look-out on all sides. Here, then, we have an animal 
with a keen power of sight, of hearing, and of feel- 
ing ; and if you have ever watched a prawn hunting 
over the scent of a piece of meat which has been 
dropped into an aquarium, you will not doubt that 
he has also the sense of smell, though it is difficult 
to point out exactly where the smelling organ is.* 
And now suppose that he has scented or caught 
sight of his prey, whether it be a piece of dead 
flesh or a soft tender living shrimp, he darts down 
upon it, and seizing it with his second pair of feet 
(cl, Fig. 56), which have large pincers,, picks it to 
pieces with his mouth and claws, and eats it, much 
as a child eats a biscuit held in its hand, but not 
with the same kind of mouth. If you will get hold 
of a prawn and try to make out its jaws, you will 
* There has been much discussion as to the position both of the smell- 
ing and hearing organs. It seems, however, from Mr. Spence Bate's 
experiments, that the ear must be at the base of the smaller antennae, 
and probably the organ of smell is at the base of the large ones. 
M 
