ANNULOSA: CRUSTACEA. 



205 



last thoracic somite — immediately in front of the abdomen — 

 carries a pair of the walking or ambulatory legs, each consist- 

 ing of a short basal piece, or " propodite," and of a long jointed 

 " endopodite," the " exopodite" not being developed. The 



yig. 62. — Morphology of Lobster. i. Lobster with all the appendages, except the 

 terminal swimmerets, removed, and the abdominal somites separated from one 

 another, en Carapace ; i Telson. 2. The third abdominal somite separated, i 

 Tergum ; s Sternum ; ^ Pleuron ; a Protopodite ," 6 Exopodite ; c Endopodite. 3. 

 One of the last pair of foot-jaws or maxiUipedes. e Epipodite ; £ Gill ; the other 

 letters as before. 



next tlioracic segment carries another pair of ambulatory limbs, 

 quite similar to the last, except for the fact that the protopo- 

 dite bears a process which serves to keep the gills apart, and 



