OUR CARCINOLOGICAL FRIENDS. &3 
claw, examine somewhat more closely one of these 
animals. Observe the two bead-like compound 
eyes, supported on long stalks, which can be read- 
ily withdrawn into the protecting shield of the 
carapace. The manner of this support, allowing 
of vision in almost every direction, has given to 
the group in which this structure is found the 
name of the stalk-eyed crustaceans, to which, in 
addition, the lobsters, crayfishes, hermits, and 
shrimps, etc., belong. The two pairs of feelers in 
front of the eyes, known as antenne and anten- 
nules, are of peculiar interest as examples of 
combined organs, for, apart from acting in their 
capacity as feelers alone, they seem to subserve the 
functions of smelling and hearing, the auditory 
apparatus being lodged in the base of the smaller 
pair. The feet are ten in number, a feature dis- 
tinctive of the so-called ten-footed or decapod crus- 
taceans. At first sight a crab appears to have no 
tail, but if the animal is turned over on its back, 
the tail—it is true, a comparatively short one— 
will be seen to be safely tucked under the body. 
If we take by way of comparison in our studies 
a lobster or a crayfish, we soon perceive that there 
is an entirely different disposition of this part of 
the body—that the tail, or more properly the abdo- 
men, is stretched out beyond the body proper, and 
that it is greatly elongated in relation to the length 
of the animal. We thus recognize two distinct 
groups of ten-legged stalk-eyed crustaceans: the 
short-tailed forms, or crabs (Brachyura), and the 
opposite or long-tailed forms, such as the lobster, 
