FISHERIES, GAME AND FORESTS. 197 



netting of only one-fourth inch square mesh. A very few were caught in the weir, 

 but these were as nothing compared with the great numbers of this species seen 

 spawning both above and below the trap. 



Differences between the Brook and the Lake Lampreys. The Brook Lamprey not 

 only differs from the Lake Lamprey in structure and in number, arrangement and size 

 of teeth, but also in size, color and habits. They are very small, averaging not over 

 eight inches in length and less than half an inch in diameter. Many of the adults 

 weigh less than one half ounce each, and it is doubtful if they ever exceed an ounce 

 in weight. They do not have as great range in size and color as do the Lake 

 Lampreys. Their color is almost always dark above, slightly mottled with some 

 darker and lighter washings, and light beneath. 



The males do not have a distinctly marked dorsal ridge, as in the Lake Lamprey 

 (see illustration No. 1, a), neither is the anal fin of the female as conspicuous. 

 Besides the facts shown that they are not parasitic, do not feed in the adult state, 

 live only a few days as adults, do not run up stream to spawn, but spawn at that part 

 of the stream where they transform, if the conditions are favorable for spawning beds, 

 and do not spawn at the same time as the Lake Lampreys, — they also differ in the 

 size of their spawning beds, which are only one third or one fourth the size of those 

 of the Lake Lamprey; also in their proximity to one another, being crowded even 

 more closely together than are those of the larger species (Compare illustrations Nos. 

 9 and 10); also differing in the size of the material they move, being able to move 

 material only about one fifth as large as that moved by the Lake Lamprey; in 

 the selection of spawning sites, being satisfied with smaller pebbles in the sand and 

 unable to use certain shallows where larger stones are found on the bottom, but which 

 afford ideal sites for the larger lampreys. If there are to be found pebbles as large as 

 ordinary playing marbles mixed with the sand the Brook Lampreys will be able to 

 establish spawning beds there and will be satisfied with the site, while the Lake 

 Lampreys will not spawn unless there are also pebbles at least as large as hens' eggs. 

 As a consequence it often happens that shallows which, on account of the nature of the 

 bottom, are not at all suitable for one kind may be perfectly well adapted for the spawn- 

 ing requirements of the other. Our illustrations show this plainly. Illustrations Nos. 8 

 and 9 are of the spawning site of the Brook Lamprey. Here there were scores of these 

 lampreys spawning, the stakes in the water marking their spawning beds, but a few 

 weeks later we visited the same site and found only two beds of the Lake Lamprey. 

 This was because the condition of the stream bed, while favorable to one was unfavor- 

 able to the other, the bottom being covered with sand and small pebbles. At the first 

 riffles or shallows below the site above mentioned the current and depth of water 

 presented perfect conditions for a spawning site, but not one spawning bed or lamprey 



