6 FISHES OF ILLINOIS 



structure, in taxonomic relations, in physiological activities, and 

 in relations to nature. They are not true fishes, their primitive 

 skeletal structures, the total absence of limbs and limb-bases, 

 the very highly specialized suctorial mouth by means of which 

 they attach themselves to their victims to devour their flesh and 

 blood, their peculiar and numerous purse-shaped gills, and their 

 single median nostril distinguishing them easily from the true 

 eels and from all other fish-like vertebrates except their marine 

 relatives, the hagfishes. From the hagfishes they are distin- 

 guished by having functional eyes in the adult, and by the fact 

 that their single nasal tube does not open into the mouth. 



Lampreys are found in the coastal and inland waters of the 

 temperate regions of both hemispheres, most species passing a 

 part of their lives in salt water. A number of kinds, however, 

 live entirely in fresh water, and all spawn in fresh water so far as 

 known. Species of Petromyzon are found along the coasts and 

 in the rivers of Europe, West Africa, Japan, and North America, 

 the great sea-lamprey of Europe and America (P. marinus) being 

 represented in the interior waters of New York by a land-locked 

 variety. Some four other genera are American, two of these 

 (Ichthyomyzon and Lampetra) being found in our state or in 

 neighboring waters of the Mississippi Valley and eastern United 

 States. 



The common names given to lampreys are numerous. They 

 are called variously, in this country and in England, " lam- 

 preys, " "lamperns, " "lampers, " "lamper eels," or even (by 

 misnomer) simply "eels. ,: The name "blood-sucker" is not 

 uncommonly applied to them by our fishermen. 



All lampreys are carnivorous, and most species, in feed- 

 ing, attach themselves to the bodies of fishes by means of the 

 sucking mouth, rasping off the flesh and sucking the blood of 

 their helpless victims, which swim about unable to dislodge 

 them. The ring-muscle of the mouth-disk works all the teeth 

 at once against the selected surface, and both scales and skin 

 are soon bored through. The relentless voracity of these fear- 

 ful pests of our fresh waters is shown by the deep holes* which 

 they make in the living bodies of their victims, and by their 

 own intestines gorged 'with blood and flesh. Their hold is prob- 

 ably seldom loosened by any fish, unless by accident. The 



power of suction exerted by the buccal funnel, without the aid 



i 



* For photographs showing the work of lampreys see Surface, Bull. U. S. Fish Comm., 

 1898, pp. 209-215; and 4th Ann. Rep. Comm. Fish, Game, and For., N. Y., 1898, pp. 191-245. 



