DEC A POD A. ASTACW/E. 



MACROURA. 



GENUS ASTACUS. Fabr. 



CANCER. Linn. 



CANCER (ASTACUS.) Penn: 

 ASTACUS. Fabr. Latr. Leach, Edw. 



Generic Character. External antenna inserted beneath, and 

 external to the internal ; the peduncle thick ; the second and third 

 joints subcylindrical, covered by a moveable scale, which is broad 

 in the middle, narrowed at each extremity, and acuminate. In- 

 ternal antennce with two short setae. External pedipalps with 

 the second joint very broad and thick ; the terminal portion ra- 

 ther thick and evenly curved. First pair of feet unequal, tu- 

 mid ; the wrist short, rounded, and placed in the same line with 

 the arm ; the hands only slightly tuberculated ; second and third 

 pairs slender, filiform, didactyle ; fourth and fifth pairs mono- 

 dactyle. Carapace smooth, with a strong transverse furrow 

 the rostrum short, triangular, depressed, and with not more than 

 one tooth on each side. Thorax with the last joint moveable. 

 Abdomen very smooth ; the terminal or caudal segment armed 

 with a small tooth on each side, near the extremity, which is 

 rounded. 



A FRESHWATER genus, very properly separated by Edwards 

 from the lobsters. 



