..... Click the link for more information. ). As in the other member of the order, the hagfish hagfish, primitive marine fish of the order Cyclostomata, or jawless fishes (see cyclostome), of worldwide distribution in cold and temperate waters. Its rudimentary skeleton, of cartilage rather than bone, has a braincase, but no jaw.
..... Click the link for more information. , the adult lamprey retains the notochord notochord , in biology, supporting rod running most of the length of animals of the phylum Chordata and present at varying times in the life cycle. Composed of large cells packed within a firm connective tissue sheath, the notochord lies between the neural tube
..... Click the link for more information. , the supporting structure that in higher vertebrates is found only in the embryo. An ancient fish that still resembles fossils that are 360 million years old, the lamprey lacks a sympathetic nervous system, a spleen, and scales. Most adult lampreys are parasitic, sucking the blood of other fishes. The horny teeth, set in the circular, jawless mouth, attach to the prey and the lamprey feeds as it is carried along. Lampreys have an anticoagulant in the saliva that keeps the blood of the victim fluid. Some freshwater lampreys eat flesh as well as blood.
Lampreys resemble eels eel, common name for any fish of the 10 families constituting the order Anguilliformes, and characterized by a long snakelike body covered with minute scales embedded in the skin.
..... Click the link for more information. in external appearance and, although not related to the true eels, are sometimes called lamprey eels. When not attached to prey, they swim with undulating movements. The marine lampreys normally migrate into freshwater to spawn, and some populations have become landlocked in freshwater.
The sexes are separate in lampreys and fertilization is external. The parents die shortly after the eggs are deposited in a nest. The larvae, called ammocoetes, are about 1-4 in. (6 mm) long. They are transparent, eyeless filter-feeders and live in muddy river bottoms, eating particles of organic matter. Ammocoetes are used in zoology courses to demonstrate a theoretically primitive vertebrate construction. At about five years of age they metamorphose into the adult, parasitic form. In some species the adult does not feed and remains the size of the larva.
There are 7 genera and about 25 species of lampreys, with 13 species in the United States. The Atlantic lamprey, Petromyzon marinus, found on both sides of the Atlantic, has become well established in the Great Lakes, where it is considered a serious pest by the fishing industry. Lampreys are classified in the phylum Chordata Chordata , phylum of animals having a notochord, or dorsal stiffening rod, as the chief internal skeletal support at some stage of their development. Most chordates are vertebrates (animals with backbones), but the phylum also includes some small marine invertebrate
..... Click the link for more information. , subphylum Vertebrata, class Agnatha, order Cyclostomata, family Petromyzontidae.
lamprey
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lamprey
lamprey [′lam·prē]
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