212 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
are sufficiently developed tliey metamorphose into adults, find their way down the 
inlet into the lake, and begin the same kind of parasitic bloodsucking life that their 
parents led. Thus is the cycle of life completed for these creatures. 
In structure and zoologic position the lampreys are the lowest vertebrates found 
in this region, being placed at the very foot of the list of fishes and by most recent 
authors they are even denied admission into the class of fishes. The class to which 
they belong is Marsipobranchii, or u pouch gill,” because the gills form a series of 
pouches, seven on each side of the head. They receive their water through as many 
independent gill-openings. 
The adult lamprey swims in the water like a fish, only with more of a wriggling 
or snake-like movement, but it does not have paired fins placed as in the true fishes. 
The only organs that it has that functionate as fins are membranous expansions on 
its back and on the dorsal and ventral sides of its tail. 
As will be seen from the figure of the mouth (p. 211), it has no jaws, but its mouth 
is a large circular disk, thickly studded with large, strong, chitiuous spines or teeth, 
which enable it to more securely grasp its victim. This disk is surrounded by a softer 
membrane, which readily fits tightly over any surface and makes it possible for the 
animal to adhere quite firmly to an object by suction when the piston-like tongue in 
the center is drawn back. Having fastened itself by this wonderful mouth, which is 
larger around than its head, it rasps away with the saw-like teeth on its tongue, using 
nearly 150 other teeth, until it has worn through the thick skin or scales of its victim. 
Then it has nothing to do but to remain attached to the fish and be carried around by 
it, sucking blood when it is hungry, and occasionally rasping away at its raw flesh, 
making the hole deeper and deeper until finally the abdominal wall is completely 
perforated and the body cavity penetrated. Often the intestines or other organs of 
the fish are attacked and cut to pieces, but more frequently the lamprey fastens itself 
at another place if its victim has any blood left, or if not it seeks another fish. 
The intestines protruding and the blood escaping from the deserted wound, in a 
great many cases sooner or later cause the death of the fish, which are often seen 
swimming in the lake in the miserable condition just described. The injured fish does 
not always die, but in every case it is seriously weakened and reduced in flesh and 
blood, and in the power of fully reproducing its kind. Among some specimens 
recently collected for study here was a bullhead or horned-pout ( Ameiurus nebulosus) 
that had been so severely attacked by a lamprey that its stomach protruded through 
the hole in the side. This fish was kept alive in a tank (for the purpose of observing 
its condition) for three weeks. 
Last spring (1897), when using a collecting seine under the permission and direction 
of the New York Fisheries, Game, and Forest Commission, the writer found by actual 
experiment that it was easy to distinguish the bullheads that had been attacked by 
lampreys, even when they were purposely turned over so that the holes were not visible. 
The injured fish loses entirely its rich golden hue, and, assuming a sickly appearance, 
grows paler and weaker. It is not at all uncommon to find dead fish along the 
shores of Cayuga Lake, and upon examination the marks of the lamprey may be seen. 
Among such fish recently found are the bullhead or catfish (Ameiurus nebulosus ), 
suckers (Catostomus), carp (Gyprinus carpio), lake herring (Argyrosomus artedi), and 
pickerel ( Lucius reticulatus). Other species of food-fish are also injured. It is a 
serious enemy of the sturgeon ( Acipenser rubicundus), one of which was caught in 
