The Cyclostomes, or Lampreys 503 



stream to another nest. When disturbed, they often start 

 tip-stream for a short distance, but soon dart down-stream with 

 a veloctiy that is almost incredible. They can swim faster 

 than the true fishes, and after they get a start are generally 

 pretty sure to make good their escape, although we have seen 

 them dart so wildly and fractically down-stream that they 

 would shoot clear out on the bank and become an easy victim 

 of the collector. This peculiar kind of circumstance is most 

 likely to happen with those lampreys that are becoming blinded 

 from long exposure to the bright light over the clear running 

 water. If there is a solitary individual on a nest when dis- 

 turbed, it may not return to that nest, but to any that has 

 been started, or it may stay in the deep pool below the shallows 

 until evening and then move some distance up-stream. When 

 the nest is large and occupied by several individuals, those 

 that are disturbed may return to any other such nest. We 

 have never seen evidence of one female driving another female 

 out of a spawning-nest; and from the great number of nests 

 in which we have found the numbers of the females exceeding 

 those of the males, we would be led to infer that the former 

 live together in greater harmony than do the males. 



"Under the subject of the number of eggs laid, we should 

 have said that at one shake the female spawns from twenty 

 to forty. We once caught in fine gauze twenty-eight eggs from 

 a female at one spawning instant. In accordance with the 

 frequency of spawning stated, and the number of eggs contained 

 in the body of one female, the entire length of time given to the 

 spawning process would be from two to four days. This agrees 

 with the observed facts, although the lampreys spend much 

 time in moving stones and thoroughly covering the nests with 

 sand. Even after the work of spawning and moving stones 

 is entirely completed, they remain clinging to rocks in various 

 parts of the stream, until they are weakened by fungus and 

 general debility, when the gradually drift down-stream. 



" In forming nests there is a distinct tendency to utilize 

 those sites that are concealed by overhanging bushes, branches, 

 fallen tree-tops, or grass or weeds, probably not only for con- 

 cealment, but also to avoid the bright sunlight, which sooner 

 or later causes them to go blind, as it does many fishes when 



