FISHERIES, GAME AND FORESTS. 221 



a cloud of sand with their tails that their eggs are at once concealed and covered. As 

 the eggs are adhesive and non-buoyant, the sand that is stirred up adheres to them 

 immediately, and covers most of them before the school of minnows in waiting just 

 below the nest can dart through the water and regale themselves upon the eggs of 

 these enemies of their race ; but woe to the eggs that are not at once concealed. We 

 would suggest that the function of the characteristic anal fin, which is possessed only 

 by the female, and only at this time of year, may be to aid in this vastly important 

 process of stirring up the sand as the eggs are expelled ; and the explanation of the 

 absence of such a fin from the ventral side of the tail of the male may be found in the 

 fact that it could not be used for the same purpose at the instant when most needed, 

 since the male is just then using his tail as a clasping organ to give him an essential 

 position in pairing. As soon as they shake together they commence to move stones 

 from one part of the nest to another, to bring more loose sand down over their eggs. 

 They work at this from one to five minutes, then shake again ; thus making the 

 intervals between mating from one to five minutes, with a general average of about 

 three and one half minutes. 



Although their work of moving stones does not appear to be systematic in 

 reference to the placing of the pebbles, or as viewed from the standpoint of man, it 

 does not need to be so in order to perfectly fulfill all the purposes of the lampreys. 

 As shown above in the remarks on the spawning habits of the Brook Lampreys, the 

 important end which they thus accomplish is the loosening and shifting of the sand to 

 cover their eggs ; and the more the stones are moved, even in an apparently indis- 

 criminate manner shown, the better is this purpose achieved. Yet, in general, they 

 ultimately accomplish the feat of moving to the lower side of the nest all the stones 

 they have placed or left at the upper margin. At the close of the spawning season, 

 when the nest is seen with no large pebbles at its upper side, but quite a pile of stones 

 below, it can be known that the former occupants completed their spawning process 

 there; but if many small stones are left at the upper edge and at the sides, and a large 

 pile is not formed at the lower edge, it can be known that the nest was forsaken or the 

 lampreys removed before the spawning process was completed. The stones they move 

 are often twice as heavy as themselves, and are sometimes even three or four times as 

 heavy. Since they are not attempting to build a stone wall of heavy material, there is 

 no occasion for their joining forces to remove stones of extraordinary size, and they 

 rarely do so, although once during the past spring (1900) we saw two Lake Lampreys 

 carrying the same large stone down stream across their nest. This was at the spot 

 which we had photographed a few weeks earlier, and here reproduce as Nos. 8 

 and 9. Although this place was occupied by scores of Brook Lampreys, there were 

 but three pairs of Lake Lampreys seen here. It is true that one of these creatures 



