The Cyclostomes, or Lampreys 179 
it is ready to be used as a spawning bed or nest. A great many 
nests are commenced and deserted. This has been left as a 
mystery in publications on the subject, but we are well con- 
vinced that it is because the lampreys do not find the requi- 
sites or proper conditions of bottom to supply all their needs 
and fulfill all conditions for ideal sites. 
