COMMON RIVER CRAYFISH. 



DEC A POD A. 



MACROUBA. 



237 



ASTACIDJE. 



COMMON RIVER CRAYFISH. 



A stacus fluviatttis. Auct. 



Specific Character. Rostrum as long as the peduncle of the external antennae, 

 with a slight elevation along the middle, and a small tooth on each side about 

 one-third from the extremity. Carapace granulated. 



Cancer fluviatilis, 

 A stacus, 

 Cancer A stacus, 

 A stacus fluviutilis. 



RONDEL, Poiss. II. p. 10. 



GESNER, ALDROV. et al. auct. 



LINN. Syst. Nat. II. p. 1051. 



FABR. Suppl. p. 406. LATR. Hist. Nat. Crust. V. p. 



235. LEACH, Diet, des c. Nat. EDW. Hist, des 



Crust. II. p. 330. 



THIS, the only European species of the genus Astacus, 

 may be readily known from others by the characters above 

 given ; although the general aspect of the whole of them is 

 so similar, that they might at a cursory glance be readily 

 confounded. 



