THE CYCLE OF LIFE 467 



after the animal is dead. Both sexes work at the nest- 

 making, and the males sometimes make considerable 

 preparations before the females arrive on the scene. 

 Sometimes two lampreys will unite their energies in Ufting a 

 heavy stone. 



When the nest is ready, or while it is being prepared, 

 the female lamprey lays her eggs within the circle, chnging 

 as she does so to a large stone. At the same time the male 

 seizes her by the top of the head, and the two bodies are 

 very rapidly vibrated for two or three seconds, during which 

 the milt or seminal fluid is shed upon the eggs. Fertiliza- 

 tion is external. The same remarks might be made in 

 regard to the brook-lampreys — Lampetra planeri in Europe 

 and Lampetra wilderi in North America. ' The females,' 

 according to Forbes and Eichardson, ' spawn in shallow 

 water, and, as a rule, where there is some current over 

 pebbly or stony bottom near the headwaters of a stream. 

 During the spawning process the females chng with their 

 oval mouths to pebbles or stones, and are clasped at the 

 nape by the suctorial discs of the males '. In the case 

 of the river lamprey, a good many couples combine to make 

 the nest and use it in common. The surface of the eggs 

 is covered with an adhesive stuff, to which sand grains 

 adhere, so that the eggs sink. Moreover, they say that 

 the two parents proceed at once to loosen some stones at 

 the upstream side of the nest, so that the loosened sand 

 buries the eggs. There may be several spawnings at short 

 intervals, and then the parents pass down stream to die. 

 For that is the most remarkable fact in the story of the 

 lampreys, that the one generation comes to an end in giving 

 the next generation a beginning. Reproduction is often 

 the beginning of death, but here the end comes quickly. 



