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Platyhelminthes
Related Category: Zoology: Invertebrates ...
: Platyhelminthes
Members of this
Flatworms are unsegmented, bilaterally symmetrical worms that lack a coelom (acoelomate) but that do have three germ layers. Some forms are free living but many are parasitic.
Invertebrates from several major divisions (phyla): For example Annelida, Chordata, Cnidaria, Ctenophora and Platyhelminthes
Habitat:
Open Waters
Animal Type:
Invertebrates
Diet:
Zooplankton
Size: ...
Phylum Platyhelminthes ("flat worms") includes some of nature's biggest freeloaders. Two-thirds of the 13,000 species in this taxon are parasitic, including the ultimate moocher, the tapeworm.
The flatworms (Platyhelminthes, Greek "platy"': flat; "helminth": worm) are a phylum of relatively simple soft-bodied invertebrate animals. Flatworms are found in marine, freshwater, and even damp terrestrial environments.
"Acoel Flatworms: Earliest Extant Bilaterian Metazoans, Not Members of Platyhelminthes". Science 283 (5409): 1919-1923. doi:10.1126/science.283.5409.1919. ISSN 0036-8075. PMID 10082465.
^ Todaro, Antonio. "Gastrotricha: Overview".
The ovary is, as in many Platyhelminthes, duplex; one part, the germary, being an organ for the production by cell multiplication of the germ-cells or eggs.
They are Digeneans (Platyhelminthes) and use snails as intermediate hosts. Inside this host, larvae of the worm develop into large sack-like structures filled with metacercariae (another larval stage).
The major invertebrate phyla are porifera (sponges), platyhelminthes (flatworms), nematoda (round worms), annelida (earthworms, marine worms and leeches), cnidaria (jellyfish, coral and sea anemones), mollusca (octopus, nautilus, squid, slugs, ...
Phoronida (phoronids)
Placozoa
Platyhelminthes (flatworms)
Porifera (sponges)
Priapula (priapulans)
Rhombozoa (rhombozoans)
Rotifera (rotifers)
Sipuncula (sipunculan worms)
Tardigrada (water bears) ...
 See also: Flatworm, Diver, Cnidaria, Snail, Crustacean
  
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