Cnidaria

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• Cnidaria
• Anthozoa
• More species than Hydrozoa or Scyphozoa
• No medusa stage
• Polyps more complex than in other classes
• Gut contains septa to add surface area for
  digestion of prey
• Passive suspension feeders and predators
• Solitary forms
• Sea anemones polyps may be very large
• Colonial forms
• Corals
• Stony corals branching and doming (massive)
• - Some build reefs in tropics
• Soft corals
• Precious corals Protein skeleton spicules
• Gorgonians (sea whips, sea fans) Tough protein
  skeleton
• Sea pens No skeleton
• Sea pansies No skeleton some bioluminescent

Anthopleura xanthogrammica
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Branching Corals
Doming Corals
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Soft Corals
Precious Corals
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• Cnidaria
• Anthozoa
• More species than Hydrozoa or Scyphozoa
• No medusa stage
• Polyps more complex than in other classes
• Gut contains septa to add surface area for
  digestion of prey
• Passive suspension feeders and predatorsolitary
  forms
• Sea anemones polyps may be very large
• Colonial forms
• Corals
• Stony corals branching and doming (massive)
• - Some build reefs in tropics
• Soft corals
• Precious corals Protein skeleton spicules
• Gorgonians (sea whips, sea fans) Tough protein
  skeleton
• Sea pens No skeleton
• Sea pansies No skeleton some bioluminescent

Anthopleura xanthogrammica
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Gorgonians (Sea Whips)
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Gorgonians (Sea Fans)
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• Cnidaria
• Anthozoa
• More species than Hydrozoa or Scyphozoa
• No medusa stage
• Polyps more complex than in other classes
• Gut contains septa to add surface area for
  digestion of prey
• Passive suspension feeders and predators
• Solitary forms
• Sea anemones polyps may be very large
• Colonial forms
• Corals
• Stony corals branching and doming (massive)
• - Some build reefs in tropics
• Soft corals
• Precious corals Protein skeleton spicules
• Gorgonians (sea whips, sea fans) Tough protein
  skeleton
• Sea pens No skeleton
• Sea pansies No skeleton some bioluminescent

Anthopleura xanthogrammica
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Sea Pens
9

• Cnidaria
• Anthozoa
• More species than Hydrozoa or Scyphozoa
• No medusa stage
• Polyps more complex than in other classes
• Gut contains septa to add surface area for
  digestion of prey
• Passive suspension feeders and predators
• Solitary forms
• Sea anemones polyps may be very large
• Colonial forms
• Corals
• Stony corals branching and doming (massive)
• - Some build reefs in tropics
• Soft corals
• Precious corals Protein skeleton spicules
• Gorgonians (sea whips, sea fans) Tough protein
  skeleton
• Sea pens No skeleton
• Sea pansies No skeleton some bioluminescent

Anthopleura xanthogrammica
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Sea Pansies
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• Cnidaria
• Cubozoa
• Sea wasps, Box jellyfish
• Small medusae
• Life cycles poorly known include polyp stage
• Highly toxic
• Eat fishes, worms, arthropods

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• Ctenophora
• Comb jellies
• Exclusively marine (100 species)
• Radial symmetry
• Eight rows of ciliary combs
• Used for swimming video
• Carnivorous
• Lack nematocysts
• Capture prey with sticky colloblasts
• May occur in swarms
• Heavy predators on plankton, including fish
  larvae
• Body forms
• Tentaculate Planktivores
• Lobate - Ctenophorivores

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• Ctenophora
• Comb jellies
• Exclusively marine (100 species)
• Radial symmetry
• Eight rows of ciliary combs
• Used for swimming
• Carnivorous
• Lack nematocysts
• Capture prey with sticky colloblasts
• May occur in swarms
• Heavy predators on plankton, including fish
  larvae
• Body forms
• Tentaculate Planktivores
• Lobate - Ctenophorivores

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Pleurobrachia
Tentaculate
Beroe
Lobate
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• Worms
• Body shape very common in invertebrates
• Especially in mobile invertebrates
• Flexibility
• Maneuverability
• Bilateral Symmetry
• Cephalization
• Head end with
• Accumulation of nerve tissue (brain)
• Sensory structures
• Anterior Posterior
• Dorsal - Ventral
• Left - Right

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Fig. 7.12
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• Platyhelminthes
• Flatworms - Dorsoventrally flattened
• Simplest bilaterally symmetrical organisms
• First organs and organ systems
• Central nervous system
• Simple brain coordinates muscle movements
• Incomplete digestive system
• Mouth but no anus
• Similar to Cnidaria and Ctenophora
• Mesoderm
• Cell layer between endoderm and ectoderm
• Gives rise to muscles, reproductive system

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• Platyhelminthes
• Turbellaria
• Mostly free-living carnivorous species
• Most commonly seen (Why?)
• Some live as commensal animals inside other
  invertebrates (oysters, crabs, etc.)

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• Platyhelminthes
• Trematoda (Flukes)
• Most species (6000)
• Parasitic Feed on tissues, blood, gut contents
• Complex life cycles
• Adults live in vertebrate host (fish, whale,
  bird)
• Larvae may inhabit invertebrates (intermediate
  hosts)
• Vertebrate eats intermediate host (clam, snail,
  etc.)
• Cestoda (Tapeworms)
• Parasitic
• Live in vertebrate intestines
• Head attaches to intestine wall with suckers or
  hooks
• Gutless absorb nutrients through body wall
• May reach 50 feet!! (sperm whales)

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• Nemertea
• Ribbon worms
• Cosmopolitan
• Most common in shallow, temperate regions
• Complete digestive tract
• Mouth and anus
• Circulatory system
• Use long, fleshy proboscis to capture prey
• Feed on crustaceans and worms
• May be cryptic or conspicuous
• Can reach 30 m in length!!