Echinoderms ( Phylum Echinodermata ) are a phylum of marine animals.

Echinoderms are found at every ocean depth, from the intertidal zone to the abyssal zone.

Echinoderms are also the largest phylum that has no freshwater or terrestrial ( land-based ) representatives.

Echinoderms are globally distributed in almost all depths, latitudes and environments in the ocean.

Echinoderms, such as sea stars and sea urchins, and mollusks, including squid and clams, as well as many other species are also at risk because of thinning shells and weakened skeletal structures.

pedicellariae ) is a small wrench-or claw-shaped structure commonly found on Echinoderms, particularly in sea stars ( class Asteroidea ) and sea urchins ( class Echinoidea ).

* A true endoskeleton ( that is, protective tissue derived from mesoderm ) is also present in Echinoderms.

Echinoderms ( such as the starfish ), crayfish, many reptiles, and amphibians exhibit remarkable examples of tissue regeneration.

Other studies indicate that these subcuticular bacteria may be both abundant within their hosts and widely distributed among the Echinoderms in general.

Echinoderms evolved from animals with bilateral symmetry.

Echinoderms have a mesodermal skeleton composed of calcareous plates or ossicles.

Echinoderms exhibit a wide range of colours.

Echinoderms possess a unique water vascular or ambulacral ( appendages such as " tube feet ") system.

Echinoderms also have a haemal system, and often also a perihaemal system.

Echinoderms lack specialized excretory ( waste disposal ) organs and so nitrogenous waste, chiefly in the form of ammonia diffuses out through the respiratory surfaces.

Echinoderms become sexually mature after approximately two to three years, depending on the species and the environmental conditions.

Echinoderms provide a key ecological role in ecosystems.

Echinoderms typically possess an internal skeleton composed of plates of calcium carbonate.

Echinoderms move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract.

Desor afterwards became professor of geology at the academy of Neuchâtel, continued his studies on the structure of glaciers, but gave special attention to the study of Jurassic Echinoderms.

Our inability to explain why certain people are fond of us frequently induces the same kind of ritual and malaise.

When these fields are surveyed together, important patterns of relationship emerge indicating a vast community of reciprocal influence, a continuity of thought and expression including many traditions, primarily literary, religious, and philosophical, but frequently including contact with the fine arts and even, to some extent, with science.

These moments are historical events in the lives of individual authors with which the student of comparative literature must be frequently concerned.

Office workers frequently go out there to lunch and swim during the siesta period, which, during the summer, lasts from two until five in the afternoon, when shops and offices are again open for business.

Such manipulations are frequently encountered in his essay on the suppression of the monasteries during the English reformation.

Among the most frequently quoted Biblical sentences are the Beatitudes and yet so few persons, other than scholars, really understand the true meaning of these eight blessings uttered by Jesus at the beginning of the Sermon on the Mount.

Occasional meetings are held for the whole membership, usually with a guest speaker, while smaller discussion groups meet more frequently.

For specialized types of displays, such as large three-dimensional units reproducing a product, package, human or animal figures, etc., reinforced plastics and rotationally molded vinyl plastisols are other materials frequently used.

But in the second subtype, which I take to be the one more frequently applied, only the operating expenses and not the `` cost of capital '' or `` fair return '' are apportioned directly among the various classes of service.

While costs on this order are sometimes separately charged for in residential and commercial rates, in the form of a mere `` service charge '', they are more frequently wholly or partly covered by a minimum charge which entitles the consumer to a very small amount of gas or electricity with no further payment.

) An authentic diffraction pattern is always obtained and optical properties are frequently checked.

The victims of the quacks are frequently poor people, like Mr. A., who scrape up their life savings to offer as a sacrifice to Doctor Fraud's avarice.

embassy workers are expected to entertain him according to his whim, frequently with their savings for the children's college tuition.

In France, novel approaches to the classic French plays are frequently attempted.

As the player shoots asteroids, they break into smaller asteroids that frequently move faster and are more difficult to hit.

The flowers are solitary or, more frequently, arranged in umbellate inflorescences at the end of a stem ( scape ).

Most Apiaceae are annual, biennial or perennial herbs ( frequently with the leaves aggregated toward the base ), though a minority are shrubs or trees.

The Rutherford films are frequently repeated on television in Germany, and in that country Miss Marple is generally identified with Rutherford's quirky portrayal.

When such permits to harvest are abused, it is frequently difficult to police.

Cryptic crossword puzzles frequently use anagrammatic clues, usually indicating that they are anagrams by the inclusion of a descriptive term like " confused " or " in disarray ".

The name ΙΑΩ, to which ΣΑΒΑΩΘ is sometimes added, is found with this figure even more frequently than ΑΒΡΑΣΑΞ, and they are often combined.

* Lo mein – The term means " stirred noodles "; these noodles are frequently made with eggs and flour, making them chewier than simply using water.

Among Classical Greeks, amazon was given a popular etymology as from a-mazos, " without breast ", connected with an etiological tradition that Amazons had their left breast cut off or burnt out, so they would be able to use a bow more freely and throw spears without the physical limitation and obstruction ; there is no indication of such a practice in works of art, in which the Amazons are always represented with both breasts, although the left is frequently covered ( see photos in article ).