The Prawn. 547 
They seldom enter the mouths of rivers. They feed on 
all the smaller kinds of marine animals, which they 
seize and devour with great voracity. In their turn, 
they are the prey of numerous species of fish, although 
the sharp and serrated horn in front of their head con- 
stitutes a powerful weapon of defence against the attacks 
of all the smaller kinds. At the side of the head there 
is frequently to be observed a large and apparently 
unnatural lump. This, if examined, will be found to 
contain, under the thoracic plate, a species of parasitic 
animal, which occupies the whole cavity, and there 
feeds and perfects its growth. The same tumour or 
lump may also be observed on the shrimp. 
Being in great request for the table, both shrimps 
and Prawns are eagerly sought for by fishermen, who 
catch them either in osier baskets, similar to those em- 
ployed in catching lobsters, or in a kind of net called a 
Putting-net. These, which are well known to all fre- 
quenters of the sea-coast, are five or six feet in - width, 
and flat at the bottom ; and are pushed along in the 
shallow water, upon the sandy shores, by a man who 
walks behind. There is a great number of other species 
belonging to the same family as the shrimp and prawn, 
but they are for the most part inhabitants of foreign 
seas, and what other British species exist are rare in 
comparison to the two we have described. 
Fossil crustaceans, which are apparently members of 
the same family, have also been found in France and 
Germany. 
