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Any of various fishes lacking jaws and true teeth and having a circular sucking mouth, including the hagfishes and the lampreys.

[From New Latin Cyclostomī and Cyclostomata, class names : cyclo- + Greek stoma, stomat-, mouth.]

cy·clos′to·mate′ (sī-klŏs′tə-māt′, -mĭt) adj.


(ˈsaɪkləˌstəʊm; ˈsɪk-)
(Animals) any primitive aquatic jawless vertebrate of the class Cyclostomata, such as the lamprey and hagfish, having a round sucking mouth and pouchlike gills
(Plants) of, relating to, or belonging to the class Cyclostomata
Also called: marsipobranch
cyclostomate, cyclostomatous, cyclostomous adj

jaw′less fish`

1. Also called cyclostome. any fish of the class Agnatha (and order Cyclostomata), characterized by a circular sucking mouth that lacks jaws.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.cyclostome - primitive aquatic vertebratecyclostome - primitive aquatic vertebrate  
agnathan, jawless fish, jawless vertebrate - eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms
Cyclostomata, order Cyclostomata - primitive jawless aquatic vertebrate: lampreys; hagfishes
References in periodicals archive ?
Still according to this author, the cyclostome genus Petromyzon possesses a thin network of pre-elastic fibers on the skin.
Venom gland apparatus in cyclostome braconid wasps with special reference to the subfamily Doryctinae (Insecta, Hymenoptera, Braconidae).
In the best studied example, cheilostome bryozoans, which arose in the mid-Mesozoic, today tend to out-compete the more ancient cyclostome bryozoans, but this ecological relationship did not give rise to reciprocal diversity patterns through time.
The two main taxonomic groups of agnathan or cyclostome fish are Hyperoartia, lampreys and Hyperotreti, and hagfish (for a review of agnathan ion and water homeostasis see Karnaky, 1998; Evans and Claiborne, 2009).
An unusually large cyclostome bryozoan (Pennipora anomalopora) from the Upper Cretaceous of Maastricht.
Skeletal ultrastructure and phylogeny of cyclostome bryozoans.
Testing for bias in the evolution of coloniality: a demonstration in cyclostome bryozoans.
Robertson (1903) suggested that this could occur in the steno-laemate cyclostome Crista spp.
Stereotyped axonal bundle formation and neuromeric patterns in embryos of a cyclostome, Lampetra japonica.