OUR CARCINOLOGICAL FRIENDS. §3 



claw, examine somewhat more closely one of tbese 

 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 ily withdrawn into the protecting shield of the 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 paii's of feelers in 

 front of the eyes, known as antennae 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. 



