THE LOBSTER AS A TYPE OF CRUSTACEA n 



fndofiodile 



Protojiodite 



CfiLfiodite 



endopodite. The protopodite consists of two seg- 

 ments, the first very short, and the second much 

 longer. It can easily be seen that the side-plates of 

 the tail-fan (the middle plate, as already mentioned, 

 is the telson) are simply the swimmerets of the sixth 

 abdominal somite. They are much larger than the 

 other swimmerets, and have the endopodite and 

 exopodite broadened 

 out into large plates ; 

 while the protopodite 

 is very short, and not 

 divided into segments. 



If now the third max- 

 illiped (Fig. 3) be ex- 

 amined, it will be found 

 that, like the swim- 

 meret, it consists essen- 

 tially of two branches springing from a stalk of 

 two segments. The exopodite, however, is much 

 smaller than the endopodite, and it ends in a flexible 

 lash made up of many small segments. The endo- 

 podite forms the main part of the limb, and has 

 five segments, so that, with the two segments of the 

 protopodite, there are seven segments in the main 

 axis of the limb ; the second and third segments 

 are partly soldered together, but the line of union 

 can be plainly seen. Attached to the outer side of 

 the first segment is a membranous plate, known as 

 the epipodite, on which is inserted, near its base, a 



FIG. 3 THIRD MAXILLIPED OF 

 LOBSTER. (From British Mu- 

 seum Guide.) 



