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An evolutionary trend toward the concentration of sensory equipment at the anterior end of the body.


A solid-bodied animal lacking a cavity between the gut and outer body wall.


An animal whose body cavity is not completely lined by mesoderm


a parasitic flatworm having one host in its life cycle


a parasitic flatworm having two hosts in its life cycle


having male and female reproductive organs in the same plant or animal


having male and female reproductive organs in separate plants or animals


Having two germ layers.


has three germ layers: the ectoderm, endoderm, and mesoderm.

Phylum Platyhelminthes

Phylum ???

---flattened, unsegmented worms, exhibit bilateral symmetry ---cephalization

Class Tubellaria

Phylum Platyhelminthes / Class ???

---free-living flatworms
---Dugesia(aka planaria)
---inhabits freshwater, saltwater and moist terrestrial env.
---carnivores ----hermaphroditic
---have auricles, ocelli, pharynx, and mouth

Class Cestoda

Phylum Platyhelminthes / Class ???

---parasites of vertebrates
---no head or digestive systems
---life cycle with one or more intermediate hosts in which
larvae develop (Digenetic)


head of an adult tapeworm; can contain suckers or hooks


One of the segments of a tapeworm, containing both male and female reproductive organs

Class Trematoda

Phylum Platyhelminthes / Class ???

---they are parasites
---complex life cycles with alternating sexual and asexual stages, those that parasitize humans spend part of lives in snail hosts

Human Liver Fluke Life Cycle

1) Miracidium 2) Sporocyst 3) Redia 4) Cercaria


1) First Stage of Fluke Life Cycle
---is the free swimming, ciliated larva which emerges from the trematode egg and swims about in search for the first intermediate host (eg. snail)


2) Second Stage of Fluke Life Cycle
---a saclike larval stage in the life cycle of some trematodes, which develops from a miracidium and produces several rediae


3) Third Stage of Fluke Life Cycle
---trematode larval stage that reproduces asexually to produce cercariae
---Final Stage before reaching maturity

Class Monogenea

Phylum Platyhelminthes / Class ???

---life cycle includes one host
---mainly ectoparasites
--- tegument
---hooks on anterior and posterior ends for attaching to host

Phylum Acanthocephala

Phylum ???

---phylum of elongated wormlike parasites that live in the intestines of vertebrates
---spiny-headed worms
---dieocious (separate sexes)

Phylum Rotifer

Phylum ???

--- bilateral symmetry
--- 3 germ layers,
---complete gut
--- corona(Crown)
--- foot w/ cement gland, dioecious (separate sexes)


(anatomy) any structure that resembles a crown in shape, Seen in Rotifers.


short structures projecting from a cell and containing bundles of microtubules that move a cell through its surroundings or move fluid over the cell's surface


ear-like projections on a flatworm that are sensitive to chemicals and touch


having two types of multiplication in two or more hosts. Sexual, occurs in adult or mature stage within definitive host, asexual, occurs in larval stages within intermediate host(s); velonging to subclass of trematodes Digenea (all flukes of human and veterinary importance belong to this Order) Direct life cycle - only one host required in life cycle but part of life cycle may be in the enviornment


a natural protective covering of the body

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