THE SHADS, THE EELS, AND THE LAMPREYS 301 
the teeth, the circular lip is fringed on the inside with a row 
of short and slender tentacles. 
It may be asked, What is the purpose of this formidable 
armature without jaws to work it? The use to which it is 
put has been well described by Couch :— 
“For simply biting, as in other fishes, the teeth are 
useless ; but when the breadth of the open mouth is brought 
into contact with the surface of a fish on which the lamprey 
has laid hold by producing a vacuum, these roughly-pointed 
teeth are brought forward in a manner to be able to act on it 
by a circular motion, and a limited space on the skin of the 
captive prey is thus rasped into a pulp and swallowed, so that 
a hole is made which may perhaps penetrate to the bones, from 
the torture of which the utmost energy of the victim cannot 
deliver it.” 
He mentions that he has found lampreys thus feeding upon 
the living bodies of mackerel, gurnard, coal-fish, cod, and 
haddock ; and Gunther mentions that salmon have been taken 
far up the Rhine with these formidable creatures fixed to them 
and boring into their flesh. 
Lampreys ascend the rivers from the sea in spring in 
order to deposit their spawn. It is stated that at this season 
a fimbriated crest rises on the back, probably only of the 
male, between the head and the first dorsal fin, and a corre- 
sponding adornment appears on the under part of the tail, 
behind the vent. Such a feature has its analogy in the nuptial 
livery of some of the aquatic reptiles with which some 
naturalists have been inclined to associate lampreys more 
closely than with fish. After spawning, lampreys exhibit 
much exhaustion, and deteriorate in condition in as marked 
a degree as do salmon. It has been asserted that they all 
die immediately after spawning, but of this there is no satis- 
factory evidence forthcoming; but it may be observed that 
eels are suspected of being capable only of a single effort at 
reproduction. 
