402 
PLANEirS LAMPREY. 
Petromyzon Planer!, Oitvieii. Jentns; Manual, p. 522. 
" “ Yahrell; Br. Fishes, vol. ii, p. 607. 
This species bears a near likeness to the Silver Lamprey 
and the Lampern, and on this account there is no doubt it 
has been overlooked by observers, although the difference when 
pointed out is sufficient readily to distinguish them. Its peculiar 
habits have been less noticed than those of others of this 
family; but having kept alive a couple of them, which had 
been taken, with many of the Mud Lamprey, in the Trelawny 
branch of the Looe river, I was able to discern a peculiarity 
in the manner in which they deal with their prey, after which 
I suppose them to be not a little eager. After four or five 
days the smallest of the two was seen to have a wound at the 
origin of the dorsal fin, and a considerable space of the skin 
of one side was excoriated; which I felt no douht to have been 
done by its companion; and on the eighth day a further injury 
of the same sort was inflicted; in both cases it appeared to 
have been done in the night. On the ninth day both were 
found dead, and hoth of them bore the same marks of injury, 
which was widely spread, but little more than skin deep. They 
did not at any time appear active; at least they were less so 
than the Silver Lamprey; but when at rest they adhered by 
the mouth to a fixed substance, which is not usually the case, 
if ever, with the Mud Lamprey. This species seems widely 
distributed, as well in Britain as on the continent, except in 
the more southern portion of the latter. 
Planer’s Lamprey is thicker in proportion to its length than 
the Silver Lamprey; hut it is more decisively known from this 
and the Lampern by the close approach to each other of the 
dorsal fins; while in the others there is an evident separation 
between them. It has been called the Fringe-lipped Lamprey, 
