आदिम जॉबल एक्वाटिक कशेरुकी: lampreys; हगफिश

Noun:

गोल मुँहवाली मछलियाँ, चूषमुखा,

cyclostomata's Usage Examples:

- /, ,,;- the adult lamprey among the Cyclostomata the liver underFIG.

See Cyclostomata.

LAMPREY, a fish belonging to the family Petromyzontidae (from r rpos and Ww, literally, stone-suckers), which with the hag-fishes or Myxinidae forms a distinct subclass of fishes, the Cyclostomata, distinguished by the low organization of their skeleton, which is cartilaginous, without vertebral segmentation, without ribs or real jaws, and without limbs.

In the Cyclostomata the primary embryo undergoes repeated fission without developing definite organs, and each of the numerous pieces so formed becomes a free larva, which possesses no alimentary canal.

The mechanism of protrusion in the Cyclostomata is a subject which requires further examination.

The body-wall is extensively calcified in the Cyclostomata and in most Cheilostomata, which may form elegant network-like colonies, as in the unilaminar genus Retepora, or may consist of wavy anastomosing plates, as in the bilaminar Lepralia foliacea of the British coasts, specimens of which may have a diameter of many inches.

The Cyclostomata are numerous in Palaeozoic rocks, but attained a specially predominant position in the Cretaceous strata, where they are represented by a prpfusion of genera and species; while they still survive in considerable numbers at the present day.

Cyclostomata (Busk).

Cyclostomata (q.v.).

Orders: Gymnolaemata (Sub-orders: Tripostomata, Cryptostomata, Cyclostomata, Ctenostomata, Cheilostomata), Phylactolaemata.

cyclostomata's Meaning':

primitive jawless aquatic vertebrate: lampreys; hagfishes