CH. IlJ THE CRAYFISH 49 



supply is obtained from fresh-water lakes in central Europe 

 and Russia. The species has become so scarce in Western 

 Europe as to no longer furnish an industry, and is, ap- 

 parently, being steadily pushed (or exterminated) east- 

 wards. The contents of the lakes are put up to auction 

 under the Russian Government. The lessee keeps a fleet 

 of fishers, and further pays the men so much per 60 cray- 

 fish. The marketable specimens are brought westwards 

 by easy stages, and at each halting place are put in streams 

 for a week to recover from the effects of their journey. 

 Between London and Russia there are three of these 

 stations of refreshment. The animals fetch from twelve to 

 as much as sixty shillings per hundred (wholesale prices) 

 according to the time of year and size and condition. A. 

 torrentium is also found in some lakes and pools and is 

 stated to have been taken some distance out at sea. Its 

 length is about 3 3 inches, and in colour it is a dull 

 greenish-grey, being thus admirably concealed among its 

 natural surroundings. During the daytime it usually 

 remains in holes which it digs in the bank of the stream, 

 generally from 3 to 15 inches below the water level, and 

 lies just at the mouth of its burrow with the nippers and 

 long antennae projecting out as sentinels into the open 

 water. It is very averse to strong light, and in captivity 

 always selects a well-shaded nook of the aquarium. The 

 food is very varied, living or dead, animal or plant being 

 alike acceptable: worms are a convenient food for specimens 

 in captivity, but they are also very partial to certain Algae 

 (Char a) and thickened succulent roots such as those of 

 the carrot. The human finger, gloved or bare, is readily 

 L. 4 



