620 THE AMERICAN NATURALIST. 
depth of water from six to twenty-four inches, near the bank or 
in the middle of the stream, under an overhanging bank or log, 
or in open water. The number of fish in a nest varies from 
one to thirty or forty (usually from three to twenty-five). 
On the morning of the 19th the number of lampreys 
observed was much smaller than on the preceding afternoon. 
While there were no fish present in stream A on that morning, 
there had been quite a number there on the afternoon of the 
18th. About noon of the 19th they became numerous again. 
We were on the spawning grounds till sunset on the 18th, and 
from sunrise on the 19th, and no marked migration of fish was 
observed at any time. For about two hours, however, before 
noon of the 19th we were exploring another stream, and there 
may have been a return of the fish to their spawning grounds 
at that time. Why the fish were less numerous on the morn- 
- ing of the 19th, or what became of them during the preceding 
night, it is difficult to conjecture. We have to thank Professor 
Jacob E. Reighard of Ann Arbor for numerous valuable sug- 
gestions and assistance in conducting our observations. 
Through the kindness of the editor of the American Natu- 
ralist the following note from Professor Gage has been for- 
warded to the writers, and they take pleasure in appending it 
herewith : 
As pointed out by Jordan and others who have made a special study of 
the American brook lamprey (LL. wi/deri), none have ever been found 
parasitic upon fishes, and none have ever been found in the waters of 
brooks except during the spawning season. To explain the apparent 
anomalies in the life history of the brook lamprey, Gage (Proc. Amer. 
Assoc. Adv. Sci. [1898], p. 372, and [1899] p. 256). carried on observa- 
tions in laboratory aquaria for four years and made field observations upon 
the same subject during the entire year. It was found that the brook lam- 
prey : (1) never goes to the larger waters of the lake, but remains con- 
stantly in the brooks ; (2) it attains its full size during the larval state ; 
(3) it is never parasitic, although a special cesophagus is developed as in 
parasitic forms (sea and lake lamprey), and the lingual and buccal WP 
are fairly well developed ; (4) during the transformation period the anim? 
remains under the sand like a larva (from September till April), during 
which time the eggs and zoósperms ripen ; (5) when the spawning season 
arrives (April-May) they emerge from the sand, build their nests, SpaWI 
and disappear. 
