Cestidae is a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

comb jellies Ctenophora (; : ctenophore ) is a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), and they are ...

. It is the only family in the monotypic order Cestida. Unlike other comb jellies, the body of cestids is greatly flattened, and drawn out into a long ribbon-like shape. The two

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s are greatly shortened, and two of the four

cilia The cilium (: cilia; ; in Medieval Latin and in anatomy, ''cilium'') is a short hair-like membrane protrusion from many types of eukaryotic cell. (Cilia are absent in bacteria and archaea.) The cilium has the shape of a slender threadlike proj ...

ted comb rows are reduced. The unusual body form allows the animals to swim by means of muscular undulation, as well as by using their cilia. The largest species, belonging to the genus ''Cestum'', can reach in length.

Classification

The order Cestida has one family, Cestidae, which contains two

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

: '' Cestum'' and ''

Velamen The velamen or velamen radicum ("covering of the roots" in Latin) is a spongy, multiple epidermis that covers the roots of some epiphytic or semi-epiphytic plants, such as orchid and ''Clivia'' species. The velamen of an orchid is the white or gr ...

''. Each genus contains one

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. * '' Cestum veneris'' Lesueur, 1813 * '' Velamen parallelum'' (Fol, 1869)

References

Tentaculata Ctenophore families {{Ctenophore-stub