lo Guide to tJic British Frcsh-Watcr FisJics 



sexually mature individuals migrate into tlie rivers to spawn, after 

 which they die. The specimen exhibited, 3i inches long, is from 

 the Severn. 



2. Lampern or River Lamprey, Lanqjetrafinviatilis. — This is 

 placed in a genus distinct from that of the Sea Lamprey on account 

 of differences in the dentition of the disc and tongue (fig. 3). It 

 is not spotted or marbled, and does not grow to a length of more 

 than 16 inches. It inhabits the coasts and rivers of Europe, 

 Northern Asia and Western North America; it resembles the 

 Sea Lamprey in habits, but is more alnindant. In some rivers, 

 such as the Trent, a considerable proportion of the Lamperns do 

 not migrate to the sea after metamorphosis, but pass their whole 

 Hfe in fresh water. 



3. Brook Lamprey or Planer's Lamprey , Lamjyctra 2)laneri. 

 — Tliis is very similar to tlie preceding species, but it has blunter 

 teeth, and the edges of llie disc are more strongly fringed ; the 

 dorsal fins are continuous, whereas in the Lampern they are 

 separated liy an interspace. This species ranges Irom Europe 

 tlirough Northern Asia to Japan ; it is found in small streams 

 and ditches, never goes to the sea, and grows but little, if at all, 

 after the metamorphosis, reaching a length of only 6 or 7 inches. 



ACIPENSERIDAE. 



This family inhabits the seas and rivers of Europe, Asia and 

 North America. The produced snout, with a transverse series of 

 four barbels in front of the small protractile mouth, the longi- 

 tudinal rows of bony plates on the body, and fli(> upturned tail are 

 cbaractoristic. 



4. Sturg-eon, Acipenscr stuiin (fig. 4). — The Sturgeon occurs 

 on the cuasis of eastern North America and of Eui'ope from 



Fig. 4. — Sturgeox. 



Scandinavia to the Black Sea; it ascends rivers to spawn, but 

 those that enter British rivers mav be regarded as stragglers, as 



