6 BRITISH FRESHWATER FISHES 



is formed, usually oval in form and slightly hollowed 

 out, with a pile of stones just below it. If the male 

 arrives unaccompanied he starts operations by himself, 

 but on joining him the female helps ; they fasten on 

 to the stones with their suckers, and with powerful 

 efforts loosen them and drag them down stream. 



The female now secures herself by means of her 

 sucker to some large stone near the upper end of the 

 nest, and her mate attaches himself to her in the same 

 way near her head, and winds himself partly round 

 her; then the two together stir up the sand with 

 vigorous movements, whilst the eggs and milt are 

 simultaneously deposited. The eggs are covered 

 with an adhesive substance, and particles of sand 

 stick to them, so that they sink to the bottom of 

 the nest. The pair now separate and at once 

 commence removing stones from above the nest and 

 enlarging the pile at the lower end, the sand thus 

 loosened being carried down and covering all the 

 eggs. This process is repeated at short intervals 

 until the spawning is completed, and then they leave, 

 many Lampreys being found going down stream or 

 attached to stones below the nesting-places. Accord- 

 ing to Professor Surface, all die after spawning ; the 

 intestine has atrophied, they are emaciated, their 

 skin is torn off in many places, they become stone- 

 blind and covered with fungus, and are so com- 

 pletely debilitated that recovery is out of the 

 question. 



The development of the eggs is rapid, and in from 

 ten to fifteen days the larvae are hatched ; about a 

 month later, at the end of July, when they are about 

 half an inch long, they leave the nests, where they 



