THE FRESHWATER FISHES 

 OF THE BRITISH ISLES 



CHAPTER I 



THE LAMPREYS 



Lampreys and Hag-fishes. The Lamprey family : the Sea 

 Lamprey — specific characters — size — distribution — breeding 

 — death follows breeding — structure and habits of larvae — 

 metamorphosis — habits of adult — origin of name — value as 

 food. The Lampern : differences from Sea Lamprey — distribu- 

 tion — migrations — breeding — food and habits — uses — other 

 names. Planer's Lamprey : differences from Lampern — 

 distribution — metamorphosis 



THE Lampreys {P etromyzonidce) and Hag-fishes 

 (^Myxmidce) differ widely in structure from 

 the Selachians and true fishes, and in many respects 

 are more generalized ; they constitute a distinct class, 

 the Cyclostomata or Marsipobranchii. They are 

 naked eel-shaped animals without paired fins, and 

 with the median fins supported by internal carti- 

 laginous radials, but lacking dermal fin-rays; the 

 internal skeleton is cartilaginous, and there are no 

 bones anywhere ; the terminal mouth has no jaws, but 

 there is a very muscular protrusible tongue, which 

 is armed with cuspidate horny laminae, and works 



