12 



BRITISH FRESHWATER FISHES 



Other names for the Lampern are " Stone-eel " 

 and " Nine-eyes," the nasal aperture, eye, and 

 seven gill-openings making up the count. 



THE BROOK LAMPREY or PLANER'S LAMPREY 

 (Lampetra planert) differs from the Lampern in 

 that the teeth are blunter and the edge of the 

 suctorial disc is more strongly fringed, whilst 

 the dorsal fins are contiguous or continuous, 

 separated by a notch only, and the free edge of 



FIG. 2. i. Larval Lamprey or Pride (Ammocoates}. 2. Planer's Lamprey. 



the second dorsal is usually more distinctly rounded, 

 instead of angular. 



It is a smaller species, not growing to more than 

 half the length of the Lampern, and has a different 

 distribution, for whilst both species are found in 

 Europe and Siberia, this one occurs also in Japan, 

 but is absent from America. It is common in 

 Britain to at least as far north as Perthshire, and 

 is widely distributed in Ireland. 



Planer's Lamprey is usually found in the smaller 

 streams, brooks, and ditches, and never goes down 

 to the sea. It was in this species that the trans- 

 formation of the larval Pride into the adult 



