Page:Popular Science Monthly Volume 16.djvu/828

 It will probably not be welcome news to some of our readers that the English crayfish is in all probability not entitled to the current title of Astacus fluviatilis. This name appears to belong to a larger species, sometimes called A. nobilis, hardly distinguishable from the



English one, which in France lives side by side with it. The smaller crayfish, which alone occurs in England, is known as A. torrentium. This specific title will, it is to be feared, have to be adopted, although it by implication casts a slur upon the river Isis. A. Fluviatilis has red tips to its legs and a rostrum which differs by a notch or two from that of A. torrentium. Further, and this is very curious, A. torrentium never has been found to be infested by that very interesting parasite (more interesting even than the crayfish itself), the