lAMPERN. 257 



time in fresh water. They are found in several of 

 the British rivers, but that which is most celebrated 

 for them is the Severn. In the mouths of some of 

 the larger European rivers they are sometimes 

 taken in such quantities that it is impossible to use 

 them in their fresh state ; they are therefore grilled 

 and moderately salted, and afterwards barrelled up 

 for sale, with the addition of vinegar and spices. 



LAMPERN. 



Petromyzon Fluviatilis. P. subfuscus^ suhtus suhargenteiis, pinnis 

 subviolaceis. 



Brownish Lamprey,, silvery beneath^ with somewhat violet- 

 coloured fins. 



Petromyzon fluviatilis. P. pinna dorsali posteriori angulata, 



Lin. Syst. Nat. p, 3Q4. 

 Petromyzon unico ordine denticulorum minimorum in limbo 



oris, praeter inferiores majores. Art. gen. 14. syn. 8g. sp. 99. 

 Petromyzon ordine dentium unico. Block, t. 78./. 1. 

 Lesser Lamprey. Penn. Brit, ZooL 



Length, when full-grown, from ten to fifteen 

 inches : on each side the mouth three * rows of 

 very minute teeth ; on the lower part seven teeth, 

 of which the outmost on each side is the largest | 

 and in the upper part of the mouth a large bifur- 

 cated f tooth : colour of the back brown or dusky, 

 sometimes clouded or mixed with blue ; whole 

 under sides silvery : body marked on the upper 

 part by numerous annular lines : on the lower part 

 pf the back a narrow fin, beyond which rises a 



* Dr. Bloch considers these as a single row. 

 f According to Bloch two teeth. 



