Ctenophora

=Phylum Ctenophora (meaning "comb bearing")= The phylum derives its name from the series of vertical ciliary combs over the surface of the animal. The body form resembles that of the cnidarian medusa. Various forms of ctenophores are known by other common names---sea walnuts, sea gooseberries and cat’s-eyes. Though comb jellies are, for the most part, of small size, at least one species, the Venus' Girdle may attain a length of more than 1 m (3 feet). One parasitic species is only 3 mm ( 1/8 inch) in diameter. Some ctenophores live in somewhat brackish water, but all are confined to marine habitats. They live in almost all ocean regions, particularly in surface waters near shores. Apart from a few creeping and parasitic species, ctenophores float freely suspended in the water. They are frequently swept into vast swarms, especially in bays, lagoons, coastal waters. Except for one parasitic species, all of them are carnivorous, eating myriads of small planktonic animals.

Reproduction in ctenophores is sexual and they are hermaphroditic; eggs and sperm (gametes) are produced in separate gonads along the meridional canals that house the comb rows. In most ctenophores, these gametes are released into the water, where fertilization and embryonic development take place.

Most ctenophores are colorless, although //Beroe cucumis// is pink and the Venus’s girdle //(Cestum veneris)// is delicate violet. The colorless species are transparent when suspended in water, except for their beautifully iridescent rows of comb plates. Most of the comb jellies are bioluminescent; they exhibit nocturnal displays of bluish or greenish light that are among the most brilliant and beautiful known in the animal kingdom.

Most of the nearly 90 known species of comb jellies are spherical or oval, with a conspicuous the sense organ (statocyst) at one end (aboral) of the body and a mouth at the other end (oral). The eight comb rows that extend orally from the vicinity of the statocyst serve as organs of locomotion. Each comb row is made up of a series of transverse plates of very large cilia, fused at the base, called combs. The more primitive forms have a pair of long, retractable branched tentacles that function in the capture of food. The tentacles are richly supplied with adhesive cells called colloblasts, which are found only among ctenophores. These cells produce a sticky secretion, to which prey organisms adhere/stick on contact.

Ctenophores and cnidarians were formerly placed together in the phylum Coelenterata. Modern authorities, however, have separated the cnidarians and ctenophores on the basis of the following ctenophore characteristics: (1) the lack of the stinging cells (nematocysts) that are characteristic of cnidarians; (2) the existence of a definite mesoderm in the ctenophores; (3) fundamental differences in embryological development between the two groups; and (4) the biradial symmetry of ctenophores. It is, however, generally thought that ctenophores and cnidarians share a common evolutionary ancestor.

//**Tentaculata**// all members of this class have two tentacles //**Nuda**// members do not have tentacles at any stage in their life cycle.
 * Classes of Ctenophora: **

**Student Zoo Keeper Pages of Species: (Enter Your Species Pages Below)**
Crawling Comb Jelly (Zookeeper: Sidney Baker) Venus' Girdle (Zookeeper: Taylor Cebuly) Sea Walnut - Mnemiopsis leidyi (Zookeeper: Kenzie Davidson) Sea Gooseberry (Zookeeper: Shaiann Etwara) Warty Comb Jelly (Zookeeper: Marissa Jenkins) Lobate Comb Jelly (Zookeeper: Hannah Jones) Bloodybelly Comb Jelly (Zookeeper: James K. Kanthachack) Eulampetia pancerina (Zookeeper: Savannah Kelley) Velamen parallelum (Zookeeper: Tori Lopez) Bathocyroe fosteri (Zookeeper: Heath Mcgregor) Cydippida (Zookeeper: Ramon Prieto) Sea Nettles (Zookeeper: Lindsey Rafus) Sea Walnut ( Zookeeper: Sarah Reimer) Deep-Sea Comb Jelly (Zookeeper: Paco Rodriguez) Pink Comb Jelly (Zookeeper: Paige Ryder) //Thalassocalyce inconstans// (Zookeeper: Haley Shelton) __Lobed Comb Jelly__ (Zookeeper: Jeffrey Slape) Common Northern Comb Jelly //(Zookeeper: Riley Stewart)// Comb Jellies- Cestum Veneris (Zookeeper: Jessica Tollver) Mertensia Ovum (Zookeeper Rachel Tolliver) Venus Girdle- //Cestum veneris// (Zookeeper: Ashley Veilleux) Coeloplana (Zookeeper Jayme Willingham) __Pink Slippery comb jelly__ (Zookeeper: Jesse Wilson) Pink Comb Jelly! (Zookeeper: Katie Woolen)

ctenophore. (2011). In //Encyclopædia Britannica//. Retrieved from [] divephotoguide.com tolweb.org
 * Information and Photo References:**