186 BRITISH FISH AND FISHERIES. 



where migratory in its habits, ascending the 

 rivers in the spring or summer, according to 

 the advance of the warmer season in their 

 countries. Formerly great numbers worked 

 their way up the Thames to a considerable 

 distance, in order to deposit their roe, but few 

 are now taken. In the Severn, there is a pe- 

 riodical influx of these fishes in considerable 

 numbers, during the months of April and May, 

 and also in various rivers which open into the 

 sea, along our southern coast. Many of the 

 Scottish rivers are also visited, but not until 

 summer has set in. They remain in the fresh 

 water about two months, making furrows in 

 the bed, not by boring like the salmon, but by 

 fixing their sucker upon the stones, and re- 

 moving them from their places, and at this 

 work they assiduously labour. Into these 

 furrows the eggs are deposited, and covered up. 

 The progressive motion of the lamprey in the 

 water is undulatory, like that of an eel, but 

 from time to time it seeks to moor itself to any 

 fixed object that offers, and then darts again 

 onwards. With regard to its food, soft animal 

 substances, and even fish, constitute its nutri- 

 ment. It fixes on its prey like a leech, and 

 rasps away with its hard teeth till it deeply 

 penetrates. When full-grown, this species 



