OF INVERTEBRATE ANIMALS. 
131 
through the Coral, the Star-fish, and the various kinds of animals that inhabit 
shells, that this part has been gradually becoming more complicated. 
The next class (Crustacea) we arrive at is that to which Shrimps, Prawns, 
Crabs, and Lobsters belong, a very numerous, extensive, and useful class of 
animals, abounding in our ditches, ponds, rivers, seas and. oceans. This class is 
well known on account of those individuals belonging to it which are edible ; but 
the most numerous part of them are not generally known. The size of these 
creatures varies exceedingly, some being visible only with the microscope, whilst 
others, as the Lobster and Crab, attain occasionally a very great size. They are 
all invested, as it were, in a coat of mail, and some are armed with very formid¬ 
able weapons, both for offensive and defensive warfare. However, this does not 
prevent them from becoming the food of almost every animal that approaches ; 
even the Star-fish and Sea-anemone make them their prey; whilst the Cuttle-fish, 
soft and helpless as it appears, unscrupulously attacks the largest of the tribe. 
Of the smaller kinds, there is one called Monoculus conchacea ; this little crea¬ 
ture is not invisible to the naked eye, but its parts can only be seen by the 
microscope. They are found very numerously in our ponds and ditches, often in 
so large numbers as to alter the colour of the medium in which they exist. 
Their colour is naturally brown or reddish, and when they collect together, they 
give the appearance of a yellow cloud in the water. 
The larger and higher kinds are all furnished with large claws or legs, two 
of which are generally bigger than the rest; and, having two of the joints opposed 
to each other, they form very powerful organs of prehension. For these animals 
this organ is much more useful than a hand could be, as it enables them to take 
the firmest possible hold, insomuch that they frequently have these limbs torn 
from the body by the objects they grasp. This leads me to observe another 
peculiarity of these animals; it is the facility with which their limbs grow again. 
You may remove all their legs, one or two at a time, and in the course of a 
month or six weeks they will be found to possess new ones, as big and as useful 
as those they had lost. 
The best-known forms amongst them are probably the Lobster and the Crab, 
and no one can look at these animals without being struck with the miraculous 
hinge-work of which they are composed. Look at the Lobster : it has long, 
jointed antennae, probably acting as organs of feeling; a little lower down we 
find it supplied with palpi, and powerful maxillae; then come its powerful 
pincers, by which it lays hold of its prey, and secures by its powerful gripe ; fol¬ 
lowing these we find five pair of legs serving for the purposes of locomotion; its 
whole body may be divided into segments, the upper rings of which have grown 
together, but the lower still move on each other; and they are so constructed, 
that when they contract they propel the animal backwards, and this is done with 
VOL. iv.—NO. xxvii. t 
