Platyhelminthes Characteristics
- Triploblastic, acoelomate
- Bilaterally symmetric
- Cephalization; with central nervous system
- Elongate, dorso-ventrally flattened
- Incomplete gut (gastrovascular cavity) or lack gut
- Free-living and parasitic forms
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Class Turbellaria — Free-living Flatworms
Characteristics
- Free-living; mostly aquatic
- Epidermis ciliated
- Mid-ventral mouth and pharynx
- Paraphyletic
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Planarian, Dugesia sp. (Order Tricladida), carbon-fed whole mount
See also labeled photo.
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Planarian, Dugesia sp. (Order Tricladida), stained cross-section (40x)
See also labeled photo.
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Brown Planarian, Dugesia trigrina (Order Tricladida)
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Freshwater flatworm, Mesostoma sp. (Order Rhabdocoela)
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A primitive, freshwater flatworm, Stenostomum sp. (Order Catenulida)
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Fresh-water planarians, possibly Phagocata velata (Order Tricladida), KY
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Fresh-water planarians, possibly Girardia sp. (Order Tricladida), NE
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Land Planarian, Bipalium kewense (Order Tricladida), a terrestrial flatworm native to SE Asia but widely introduced elsewhere; Phoenix, AZ
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Tapered Flatworm, Notoplana acticola (Order Polycladida), in tidepool, CA
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Long Speckled Flatworm, Enchiridium punctatum (Order Polycladida), in tidepool, CA
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Reticulated Flatworm, Phrikoceros mopsus (Order Polycladida) (collected in FL)
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Class Trematoda — Trematode Flukes
Characteristics
- Internal parasites with often complex life cycles
- Epidermis forms tegument
- Attach to host via oral and ventral suckers
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Sheep Liver Fluke, Fasciola hepatica, a parasite of sheep livers.
See also labeled photo.
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Sheep Liver Fluke, Fasciola hepatica, Cercariae (left) and Miracidia (right) larval stages found in snails (stained whole mounts).
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Schistosome, Schistosoma japonicum; fresh-water snails are intermediate host and various vertebrates are definitive host (stained whole mount).
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Chinese Liver Fluke, Clonorchis sinensis; stained whole mount.
See also labeled photo.
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Chinese Liver Fluke, Clonorchis sinensis; 2nd example.
See also labeled photo.
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Class Cestoda — Tapeworms
Characteristics
- Parasites of vertebrate guts
- Epidermis forms tegument
- Attach to host via anterior scolex
- Trunk (strobila) greatly elongated, consists of numerous segmented proglottids
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Dog Tapeworm, Taenia pisiformis, a common intestinal parasite of dogs and pigs
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Dog Tapeworm,Taenia pisiformis, microscopic view of solex, proglottids.
See also labeled photo.
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Sheep Tapeworm, Moniezia expansa, stained slide of different body regions.
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