The Cyclostomes, or Lampreys 17 
up and down from the ventral toward the dorsal side of the 
mouth. Around the mouth is a circle of soft membrane final'y 
surrounded by a margin of fimbriz or small fringe. This com- 
pletes the apparatus with which the lamprey attaches itself 
to its victims, takes its food, carries stones, builds and tears 
down its nest, seizes its mate, holds itself in position in a strong 
current, and climbs over falls. 
Mischief Done by Lampreys.—‘‘ The most cormmon economic 
feature in the entire life history of these animals is their feeding 
habits in this (spawning) stage, their food now consisting wholly 
of the blood (and flesh) of fishes. A lamprey is able to strike 
its suctorial mouth against a fish, and in an instant becomes so 
firmly attached that it is very rarely indeed that the efforts of 
the fish will avail to rid itself of its persecutor. When a lam- 
prey attaches itself to a person’s hand in the aquarium, it can 
only be freed by lifting it from the water. As a rule it will drop 
the instant it is exposed to the open air, although often it will 
remain attached for some time even in the open air, or may 
attach itself to an object while out of water. 
‘Nearly all lampreys that are attached to fish when they 
are caught in nets will escape through the meshes of the nets, 
but some are occasionally brought ashore and may hang on 
to their victim with bulldog pertinacity. 
“The fishes that are mostly attacked are of the soft-rayed 
species, having cycloid scales, the spiny-rayed species with 
ctenoid scales being most nearly immune from their attacks. 
We think there may be three reasons for this: rst, the fishes 
of the latter group are generally more alert and more active 
than those of the former, and may be able more readily to dart 
away from such enemies; 2d, their scales are thicker and stronger 
and appear to be more firmly imbedded in the skin, consequently 
it is more difficult for the lampreys to hold on and cut through 
the heavier coat-of-mail to obtain the blood of the victim; 
3d, since the fishes of the second group are wholly carnivorous 
and in fact almost exclusively fish-eating when adult, in every 
body of water they are more rare than those of the first group, 
which are more nearly omnivorous. According to the laws 
and requirements of nature the fishes of the first group must 
be more abundant, as they become the food for those of the 
