Platyhelminthes

Author: Meghan Harper
__**EXAMPLES**__: >> > > **Scolex of //Taenia solium//** >> > **//Dermophthirius//, a microbothriidmonogenean parasitic on elasmobraanchs** > > > **//Botulus microporus//, a giant digenean parasite from the intestine of a lance fish** >
 * There are five classes under the phylum platyhelminthes
 * Turbellaria: organisms that are not exclusively parasitic
 * **A marine species //Pseudobiceros bedfordi// (Bedford's Flatworm), a member of the Polycladida**
 * Cestoda: parasitic; live in digestive tracts
 * [[image:Tenia_solium_scolex.jpg width="285" height="194"]]
 * Monogenea: primarily found in skin and gills of fish
 * Trematoda: mainly parasites of mollusks and vertebrates

> //Lobatostoma manteri//, an Aspidogastrean parasite of Australian fishes
 * **Aspidogastrea: parasites of freshwater and marine mullusks and vertebrate**


 * __HABITAT__:**
 * the habitat varies for the platyhelminthea
 * some reside inside hosts and others outside their host
 * free-living or parasitic
 * marine environments
 * sheltered locations (under rocks, logs, trees, etc.)

__**TYPE OF COELOM:**__
 * Acoelomate (having no coelom)
 * lack the fluid filled body cavity
 * platyhelminthes do not have the need for diffusion of gas and metabolites


 * __ENDOSKELETON or EXOSKELETON__:**
 * endoskeleton- on the inside


 * __TYPE OF NERVOUS SYSTEM__:**
 * simple nervous system
 * two nerve cords running down either side
 * two simple brains called ganglia, which are simple bundles of nerves
 * two eyespots that help it sense light

__**FEEDER**__:
 * organisms classified as platyhelminthes obtain characteristics of various feeders
 * parasitic- live and feed off of hosts
 * detritus- feeds off of bodies and parts of non-living organic material
 * carnivore- flesh eater
 * scavenger- feeds off of dead plants or meat

__**SYMMETRY**__:
 * bilateral symmetry- left and right sides are mirror images of each other
 * implies that they have distinct top and bottom surfaces and distinct head and tail ends

__**REPRODUCTION**__: >
 * asexually
 * reproduces by splitting in two
 * have both male and female reproductive organs

__**CIRCULATORY SYSTEM**__:
 * gastrovascular cavity with one opening
 * eats small worms, insects and microscopic matter

__**ENDOTHERMIC or EXOTHERMIC**__.
 * exothermic- give off heat to the environment

__**SEGMENTATION**__:
 * no true segmentation
 * Body usually flattened dorsoventrally

__**WORKS CITED**__: "Answers.com - Do Flatworms Have an Exoskeleton." WikiAnswers - The Q&A Wiki. Web. 26 Mar. 2011. .

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"File:Tenia Solium Scolex.jpg." //Wikipedia, the Free Encyclopedia//. Web. 26 Mar. 2011. .

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"Monogenea." //Wikipedia, the Free Encyclopedia//. Web. 26 Mar. 2011. .

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"Trematoda." //Wikipedia, the Free Encyclopedia//. Web. 26 Mar. 2011. <http://en.wikipedia.org/wiki/Trematoda>.

"Turbellaria." //Wikipedia, the Free Encyclopedia//. Web. 26 Mar. 2011. <http://en.wikipedia.org/wiki/Turbellaria>.

"Worms Galore - 11/10/10." Benton Zoologists. Web. 26 Mar. 2011. <http://nashzoology.ning.com/forum/topics/worms-galore-111010?commentId=2223964:Comment:10256&xg_source=activity>.