STURGEON— LAMPREYS 



3<>3 



thirty-one larger plates, closely placed, and from eleven to thirteen on the under 

 side. The head is moderately long, triangular in form, and has round barbels, a 

 narrow upper lip, and a thick lower lip parted in the middle line. Occasionally 

 sturgeon are taken in British waters, where they become, ipso facto, the property 

 of the sovereign. 





'"';>>> 

 ^ 



- 



THE STURGEON. 



Lampreys. 



Among vertebrate animals, not included in the class of fishes, are 

 the lampreys and hag-fishes (Cyclostomata), broadly distinguished 

 from fishes by their circular, jawless, sucking mouths : they possess only one nostril, 

 are devoid of paired fins, have from six to seven gill-slits on each side of the body, 

 and their skeleton is cartilaginous. In the rivers of Europe they are represented 

 typically by the lampreys, which, by means of the fleshy lips of their round or 

 crescent-shaped sucking-mouths, adhere tightly to certain fishes, drawing back the 

 club-shaped tongue to form a vacuum, and at the same time wounding their prey 

 with the sharp lip-teeth, in order to suck the blood. Lampreys undergo a complex 

 transformation after they emerge from the egg, the larva? (long regarded as a 

 distinct animal, under the name of Ammoccetes) are blind, and live at the bottom 

 of rivers, and begin their metamorphosis into full - grown lampreys in the 

 autumn of the fourth or fifth year. The river-lampreys, which enter fresh water 

 from the sea, are about 8 inches long, and when fully developed travel back to the 

 sea, returning to the place of their birth after the lapse of some years, when they 

 are ripe for spawning. Among the three species found in Europe the sea-lamprey 

 (Petromyzon marinus), which attains a length of about 3 feet, is greenish in 

 colour with dull yellow and brown spots, and is characterised by a distinctly 

 separated dorsal fin. The river-lamprey (P. fluviatilis), on the other hand, which 

 is about 18 inches long, and occurs in nearly all the fresh waters of Europe, as also 

 in those of North America and Japan, is green above, with yellowish sides, and 



