Astacus fluviatilis. Fabricius, Ent. Syst. Suppl. p. 406. 
Latreille, Gen. Crust. V. p. 235. 
Potamobius fluviatilis. Leach, non Risso. 
Vig. 1. Potamobius astacus. 
There has been some confusion of synonyms between this species and the common lobster. 
The present editor, however, believes that the nomenclature adopted by the authorities in the 
British Museum is the more correct. In general appearance the Potamobius is a miniature 
representation of the marine Lobster, and is abundantly diffused through all the larger rivers of 
our country, as well as those of Europe generally. It is much in request for the table, under the 
name of the “ River Cray-fish.” Specimens will live for some time in a fish-tank, where their 
habits, which are very interesting, may be observed. One in possession of the writer, shed his 
outer covering so neatly, and with so little disturbance of the parts, that it was at first thought 
there were two Cray-fish instead of one in the tank. Although of a dull greenish colour when 
living, the shells turn red, when boiled, like the common Lobster. 
