FISHES. 589 



Is met with in the North Sea and Cattegat as well as in 

 the south of the Baltic. Has only once been taken in 

 Finland. 



This fish has the peculiarity of attacking other fish, 

 attaching itself to their sides by its broad mouth, and suck- 

 ing out their blood. This is often observed on these coasts 

 in the rays ; and old Bishop Gunnerus tells us that they will 

 even do so with the basking shark, never leaving the body 

 until the fish is dead. 



The sea lamprey come up rivers in spring, to spawn in 

 fresh water. 



181. P. FLUVIATILIS, L. Yanlig Nejonogon. The River 



Lamprey. D. F. 



Dusky blue above ; silvery beneath ; dorsals wide 

 apart, the hinder one joined to the tail. General form, 

 like the last, but more elongated; rarely exceeds 12 in. 

 in length, with a height of f in. and a breadth of -f- in. 

 Much rarer in the rivers of the south than in the middle 

 and north of Scandinavia, where, especially in the east, they 

 are very common. Is noticed by Widigren, in his " Fish of 

 Lulea Lapland," as very common off that coast, so it does 

 not appear that it is entirely confined to fresh water. 



182. P. PLANEKI, Bl. Igel Nejonogon. Planner's Lamprey. 



D. F. 



Length 6 in. to 8 in. Differs from the last, which it 

 resembles in colour, shape of the mouth, etc., in having 

 the two dorsals placed close together, and the body 

 being proportionably thicker; colour more blue; the 

 lip is broad and fringed, and there is a difference in the 

 arrangement of the teeth. Derives its Swedish name 

 from its similarity to a leech (igel). 

 Is far commoner than the last, at least in the south of 

 Wermland. 



Gen. Ammocoetes, Dum. 



Body, gills, and fin as in the last, but the mouth is only 

 semi-circular, with no teeth ; only a few small cirri on the 



