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Platyhelminthes

(Phylum)

Overview

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A phylum of multicellular, acoelomate animals, commonly called flatworms, which are flattened dorsoventrally and are bilaterally symmetrical, and have the epidermis (ectoderm) and gut separated by a solid mass of tissue. They include the free living Turbellaria and the parasitic Monogenea, Trematoda and Cestoda.

Incomplete or absent digestive tract; no body cavity; mostly hermaphroditic. They include free-living and parasitic forms.

Photos

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Taxonomy

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The Phylum Platyhelminthes is further organized into finer groupings including:

Classes

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Cestoda

[more]

Cestoidea

This article describes the flatworm. For the medical condition, see Tapeworm infection. [more]

Monogenea

[more]

Seriata

[more]

Trematoda

Trematoda is a class within the phylum Platyhelminthes that contains two groups of parasitic flatworms, commonly referred to as "flukes". [more]

Turbellaria

The Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms), and include all the sub-groups that are not exclusively parasitic. There are about 4,500 species, which range from 1 mm (0.039 in) to 600 mm (24 in) in length. All the larger forms are flat with ribbon-like or leaf-like shapes, since their lack of respiratory and circulatory systems means that they have to rely on diffusion for internal transport of metabolites. However, many of the smaller forms are round in cross section. Most are predators, and all live in water or in moist terrestrial environments. Most forms reproduce sexually and with few exceptions all are simultaneous hermaphrodites. [more]

At least 1,554 species and subspecies belong to the Class Turbellaria.

More info about the Class Turbellaria may be found here.

Sources

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Last Revised: October 03, 2013
2013/10/03 15:48:09