322 CARTILAGINEI.— PETROMYZONID^. 
means^ the formation of a fit receptacle for the 
deposited spawn. The Lamprey {Petromyzon 
marinus^ Linn.) ascends the rivers of Scotland 
to breed about the end of June, and remains in 
them until August. These fishes are not fur- 
nished with any elongation of the jaw, afforded 
to most of our freshwater fish, to form the re- 
ceiving furrows at this important season; but 
the want is supplied by their sucker-like mouth, 
by which they individually remove each stone. 
Their power is immense. Stones of a very large 
size are transported, and a large furrow is soon 
formed. They remain in pairs, two on each 
spawning place, and while there employed, retain 
themselves affixed by the mouth to a large stone.” 
The curious sucking-mouth is also serviceable 
to these fishes in enabling them to prey upon 
other fishes, which otherwise they would be ill- 
calculated to molest. They are known to attack 
fishes of large size, by fastening upon their flesh, 
and while affixed eating away the soft parts 
down to the bone, with their numerous small 
rasp-like teeth. 
This species is called the Sea Lamprey to 
distinguish it from another, the River Lamprey, 
called also Lampern (P. Jluviatilis). The latter 
is a permanent inhabitant of fresh water, but the 
former only ascends the rivers to spawn. Both 
are in high repute for the table, but the Lam- 
prey is of much more value than the Lampern, 
on account of its superior size. It attains two 
or three feet in length ; its ground colour is 
olive, handsomely spotted and mottled with deep 
green and dark brown ; the edges of the fins are 
reddish ; and the eyes are golden. 
