PETROMYZOxNTS OR LAMPREYS 451 



voracity of these fearful pests of our fresh waters is shown by 

 the deep holes 1 which they make in the living bodies of their 

 victims, and by their own intestines gorged with blood and 

 flesh" (S. A. Forbes and R. E. Richardson, Fishes of Illinois, 

 1908, p. 6). 



It is doubtful whether adult lampreys eat anything but fish 

 though it is often said that they take worms, insects, and decay- 

 ing animal matter. Some small creatures may come in from 

 the perforated intestines of the fishes that have been destroyed. 



Most attention has been paid to the breeding habits of 

 the brook-lampreys — Lampetra planeri in Europe and Lam- 

 petra wilderi in North America, " The females 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 cling with their oval 

 mouths to pebbles or stones, with the body streaming in 

 the current, and are clasped at the nape by the suctorial disks 

 of the males" (Forbes and Richardson, Fishes of Illinois, 1908). 



There is a lack of precise information in regard to the re- 

 production of lampreys. It is known that the reproduction is 

 associated with profound constitutional changes in the body of 

 both sexes, and that death often follows the spawning season. 

 Large marine lampreys are sometimes found lying dead in the 

 water just after the spawning — a signal instance of the nemesis 

 that often follows reproduction. We know that many insects 

 such as may-flies, and many butterflies die after reproducing, 

 and the same is true of simpler organisms like many worms, 

 and of higher organisms like the common eels. Reproduction 

 is often the beginning of the end of the individual life; in the 

 case of the lamprey (in some species at least) death follows 

 rapidly on the heels of the generative process. In regard to 

 the small American brook-lamprey {Lampetra wilderi) "spawn- 

 ing and death are said to follow so soon after the transforma- 

 tion that the parasitic stage appears to be quite passed over 

 in the life-cycle, the adults not taking food of any kind " 

 (Forbes and Richardson, Fishes of Illinois, 1908). 



The newly hatched young lamprey is spoken of as a larva, 



1 For photographs showing the work of lampreys see H. A. Surface, Bull. 

 U. S. Fish Commission, 1898, pp. 209-215 ; and 4th Ann. Report Fish, etc., New 

 York, 1898, pp. 191-245. 



