BRITISH FRESH-WATER FISHES 
also stated to partake of insects and worms. The 
manner of propulsion through the water reminds one of 
the movements of an Eel, and like that fish, the present 
species and its cousin to follow, are very tenacious, and 
will live for quite a long period out of their native 
element. In olden days a dish of Lampreys was con- 
sidered a great delicacy, but to-day this interesting 
tenant of our rivers is mostly used as bait for other 
fishes. 
Brook, or Planer’s Lamprey.—Lampetra planeri (Fig. 
30). The larval form of the Lamprey is known as the 
Pride. It has no teeth, but on the front of the mouth 
there is a fringe of barbules which serves the purpose of a 
sieve for sifting food. It resides in a tube, and although 
open at one end, the inhabitant works its way further in 
if danger threatens. ‘This larval state of existence lasts 
for three or four years, and it is not until the creature 
has attained a length of several inches that the adult 
form is reached. 
Planer’s Lamprey does not grow to a greater length 
than 8 inches, and haunts smaller streams than Lampetra 
fluviatilis. Moreover, it restricts itself entirely to fresh 
water, and does not migrate to the sea. It is well 
distributed in our smaller waterways, and extends to 
Scotland, and is common in Ireland. 
In general appearance this second species (there is a 
third species, the Sea Lamprey, Petromyzon marinus, 
which enters fresh water to spawn, and is a much larger 
fish, attaining a maximum length of 36 inches), is dis- 
62 
