Cyclostomata

Thesaurus

Noun

Cyclostomata - primitive jawless aquatic vertebrate: lampreys; hagfishesorder Cyclostomataanimal order - the order of animalsAgnatha, superclass Agnatha - superclass of eel-shaped chordates lacking jaws and pelvic fins: lampreys; hagfishes; some extinct formscyclostome - primitive aquatic vertebrateHyperoartia, Petromyzoniformes, suborder Hyperoartia, suborder Petromyzoniformes - lampreys as distinguished from hagfishesfamily Petromyzontidae, Petromyzontidae - lampreysHyperotreta, Myxiniformes, Myxinoidea, Myxinoidei, suborder Hyperotreta, suborder Myxiniformes, suborder Myxinoidei - hagfishes as distinguished from lampreysfamily Myxinidae, Myxinidae - slime-producing marine animals: hagfishes

Cyclostomata

enUK

Cyclostomata

[¦sī·klō′stō·mə·də] (invertebrate zoology) An order of bryozoans in the class Stenolaemata. (vertebrate zoology) A subclass comprising the simplest and most primitive of living vertebrates characterized by the absence of jaws and the presence of a single median nostril and an uncalcified cartilaginous skeleton.

Cyclostomata

(also Cyclostomi), a class of lower aquatic vertebrates of the superclass Agnatha. The eellike body is covered with a tough skin, which has many slime-secreting cells. There is no external skeleton. The notochord is persistent, and the internal skeleton is cartilaginous. There are no paired fins. The gills, which are in the form of pouches, are of endodermal origin. The funnel-shaped mouth is supported by a ring of cartilage (hence the name). The teeth are horny, and the tongue is used for perforating. The olfactory organ is sac-shaped, with a nasohypophyseal canal emerging from its bottom and ending in a blind sac. In the membranous labyrinth there are only two semicircular ducts.

The two subclasses of Cyclostomata, Petromyzones (lampreys) and Myxini (hagfishes), sharply differ from one another. Cyclostomata are marine, freshwater, or both. The females deposit eggs which are fertilized and develop in water. Cyclostomes are either ectoparasites of fishes or predators. Some species of lampreys are commercially valuable.

REFERENCES

Berg, L. S. Sistema ryboobraznykh i ryb, nyne zhivushchikh i iskopaemykh, 2nd ed. Moscow-Leningrad, 1955. (Tr. Zoologicheskogo instituta AN SSSR, vol. 20.)
Nikol’skii, G. V. Chastnaia ikhtiologiia, 3rd ed. Moscow, 1971.

V. D. LEBEDEV

Cyclostomata

Related to Cyclostomata: Chondrichthyes, Osteichthyes

noun

Synonyms for Cyclostomata

noun primitive jawless aquatic vertebrate: lampreys

Synonyms

order Cyclostomata

Related Words

animal order
Agnatha
superclass Agnatha
cyclostome
Hyperoartia
Petromyzoniformes
suborder Hyperoartia
suborder Petromyzoniformes
family Petromyzontidae
Petromyzontidae
Hyperotreta
Myxiniformes
Myxinoidea
Myxinoidei
suborder Hyperotreta
suborder Myxiniformes
suborder Myxinoidei
family Myxinidae
Myxinidae