98 |^a;g j?HHHS, (Stesajjs, anir IJLebiefos. [n. 



short and very thick, the terminal divisions are very 

 broad and fiat, and one of them is divided into two 

 pieces. 



I may say, therefore, that the sixth segment is like the 

 others in plan, but that it is modified in its details. 



The first segment is like the others, so far as its ring is 

 concerned, and though its appendages differ from any of 

 those yet examined in the simplicity of their structure, 

 parts corresponding with the stem and one of the divi- 

 sions of the appendages of the other segments can be 

 readily discerned in them. 



Thus it appears that the lobster's tail is composed of 

 a series of segments which are fundamentally similar, 

 though each presents peculiar modifications of the plan 

 common to all. But when I turn to the fore part of the 

 body I see, at first, nothing but a great shield-like shell, 

 called technically the " carapace," ending in front in a 

 sharp spine, on either side of which are the curious com- 

 pound eyes, set upon the ends of stout moveable stalks. 

 Behind these, on the under side of the body, are two 

 pairs of long feelers, or antenna, followed by six pairs of 

 jaws, folded against one another over the mouth, and 

 five pairs of legs, the foremost of these being the great 

 pinchers, or claws, of the lobster. 



It looks, at first, a little hopeless to attempt to find in 

 this complex mass a series of rings, each with its pair of 

 appendages, such as I have shown you in the abdomen, 

 and yet it is not difficult to demonstrate tHeir existence. 

 Strip off the legs, and you will find that each pair is 

 attached to a very definite segment of the under wall 

 of the body ; but these segments, instead of being the 

 lower parts of free rings, as in the tail, are such parts of 

 rings which are all solidly united and bound together ; 

 and the like is true of the jaws, the feelers, and the eye- 

 stalks, every pair of which is borne upon its own special 



