8 BRITISH FRESHWATER FISHES 



sucking-disc, the teeth develop, the branchial groove 

 disappears, etc. Numerous important internal 

 changes have accompanied those more easily- 

 observed, and the whole process occupies the 

 greater part of two months, from about the end 

 of August till the middle of October. Until the 

 transformation is complete the Lampreys may still 

 be captured in the sand, but they are more active 

 than the larvae which are not changing, and attempt 

 to swim away when disturbed. After the meta- 

 morphosis the young Lampreys go down to the 

 lakes, where they live on the fishes ; sometimes a 

 fish attacked has been observed to rise to the surface 

 and turn over on one side, so that the head and gills 

 of his enemy are out of the water and he is forced 

 to drop off. 



Two or three years elapse before the Lamprey 

 attains sexual maturity and seeks the streams to end 

 his career in perpetuating his race. 



This account agrees with what we know of the 

 Sea Lamprey in this country, except that the sea 

 takes the place of the lakes as the home of the adult 

 form, and, as might be expected, a larger size is 

 reached. In the sea this species lives chiefly on Cod, 

 Mackerel, etc., and it is on record that large numbers 

 attached themselves to a Basking Shark, not leaving 

 it until it was dead. Quite recently one was landed 

 at Buckie, which had fixed itself to the rudder of a 

 fishing-boat and could not be detached until the boat 

 had been beached. 



In their migrations the Lampreys are said to be 

 often carried into rivers by Salmon, and have been 

 described as ascending rapid streams by plunging 



