132 



ist Maxillipedes Protopodite forms a blade-like 

 bipartite gnathobase. Endo- 

 podite reduced. Exopodite fila- 

 mentous. The base of this 

 appendage has an attached epi- 

 podite, i.e., a gill which 'has lost 

 its respiratory processes. 



2nd Maxillipedes Endopodite is leg-like and has five 

 joints ; the two lower joints 

 have cutting edges, and along 

 with the protopodite form the 

 gnathobase. Exopodite is long 

 and filamentous. To the base 

 of this appendage a gill (podo- 

 branch) is attached. 



3rd Maxillipedes Endopodite is large and leg-like, 

 and has five joints ; the two 

 lower joints have toothed edges, 

 and along with the protopodite 

 form a strong gnathobase. Exo- 

 podite is filamentous. To the 

 base of this appendage a gill 

 (podobranch) is attached. 



Note. The protopodite is two-jointed in all the above 

 appendages except the mandibles. 



2 

 1 



Indicate the Structure and Function of the Chelae, Thoracic 

 Limbs and Swimmerets of the Crayfish. 



The chelae or "nippers.' 



For seizing food and for de- 

 fence. Protopodite two- 

 jointed. Endopodite large 

 and five- jointed ; the sec- 

 ond last joint prolonged 

 to form with the last joint 

 a double claw (chelate). 

 Exopodite absent. To the 

 base of each chela a gill 

 (podobranch) is attached. 



