Cestidae is a
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of
comb jellies
Ctenophora (; ctenophore ; ) comprise 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 ...
. 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 ma ...
s are greatly shortened, and two of the four
ciliated 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: ''
Cestum'' and ''
Velamen
Velamen or velamen radicum 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 gray covering of aerial roots (when dry ...
''. Each genus contains one
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
.
* ''
Cestum veneris''
Lesueur, 1813
* ''
Velamen parallelum''
(Fol, 1869)
References
Tentaculata
{{Ctenophore-stub