PETEOMYZON MAEINUS. 421 



though Yarrell describes two pores throug-li which the spawn is discharged. 

 There is no air-bladder. The kidneys are well developed, and their ducts open 

 into the abdominal pore. 



The fish has no limbs j but there are two dorsal fins in which rays are 

 developed. Petromyzon lives in I'ivers, where it spawns, and then goes down 

 to the sea. The eggs are small. 



Dr. Giinther enumerates four genera of true Lampreys, distinguishing 

 Petromyzon as having the maxillary tooth bicuspid^ Ichthyomyzon as having the 

 maxillary tooth tricuspid, Mordacia as having tricuspid maxillary teeth, and 

 Geotria as having four lobes on the maxillary plate. Petromyzon is the only 

 genus found in Europe, but it also extends to North America and West Africa, 

 and one species is recorded from Buenos Ayres. 



Petromyzon marinus (Linnaeus). — The Lamprey. 



The Sea Lamprey is known in France as Lamprole, in South Germany as 

 Seelamprete, in Austria it is termed Pricke, in Italy Lanqyreda, in North 

 Germany the popular name is Meerneunauge, and in Sweden Hafs-nejnoga. 



Thus widely distributed along the coasts and rivers of Europe (excepting 

 in the region of the Black Sea), it ranges southward to the west coast of 

 Africa, and is found in North America, from Nova Scotia southward. 



It is usually met with on the bottom, but swims with a snake-like move- 

 ment, and is sometimes transported adhering to the bodies of other fishes. It 

 is often taken at sea, and has been known to attack Gurnards, Mackerel, Cod, 

 and many other fishes ; and Couch mentions many examples of fish in which 

 the flesh had healed after holes had been thus rasped in the body. It has 

 occasionally fastened on to bathers, and is said to be attracted by the tar of 

 boats. Pennant speaks of one that attached itself to a stone weighing twelve 

 pounds, from which it was separated with difficulty ; and the popular name, 

 Lamprey, has been regarded as signifying stone-sucker, but we rather agree 

 with Badh'am, in deriving it from lang, long, and^;?-^;?/, pricJc, ov pride, local 

 names for the smaller River Lamprey. 



Day states that the fishery in the Severn at Worcester begins in 

 February and lasts till May. The Lamprey is taken in the Thames in May and 

 June; but Jardine tells us that it ascends the Scottish rivers about the end of 

 June, and remains in them till the beginning of August. On the Continent 

 it ascends the rivers in spring, both in North Germany and in Italy ; but the 

 period at which it enters rivers varies with the stream. Although it may 

 attack other fishes, and sometimes eat flesh from their bodies, it will feed 

 upon any kind of soft animal food. It is usually from twenty to thirty 



