Phylum Porifera The Sponges

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Phylum PoriferaThe Sponges
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Classes of Porifera

• Class Calcarea (e.g., Leucosolenia)
• Class Hexactinellida (e.g., Euplectella)
• Class Demospongiae (e.g., Spngilla)

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General Characteristics

• Most are marine a few live in fresh water one
  family Spongillidae
• Metazoan, with loosely aggregated cells,
  therefore no organs or true tissues.
• Asymmetrical or radial symmetry
• Body with pores (ostia and osculum), canals, and
  chambers through which a water current flows.

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General Characteristics

• Epidermis of flat pinacocytes
• Inner surfaces lined with flagellated collar
  cells (choanocytes)-create water currents
• matrix called mesohyl contains amebocytes
• and skeletal elements
• Skeleton of calcareous or siliceous crystalline
  spicules and/or protein fibers (spongin)

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General Characteristics

• Digestion intracellular
• Respiration and excretion by diffusion
• Nervous system absent
• All adults sessile and attached to substrate
• Asexual reproduction by buds or gemmules
• Sexual reproduction by eggs and sperm
• Free-swimming ciliated amphiblastula larvae

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Figure 12.11
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Figure 12.12a
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Class Calcarea

• also known as Calcispongiae
• have spicules of calcium carbonate
• all marine

Leucosolenia
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Leucosolenia
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Grantia (Scypha)
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Schypha (Spicules)
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Class HexactinellidaThe Glass Sponges

• Glass sponges
• have siliceous spicules,
• body often cylindrical or funnel shaped

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Class - Hexactinellida
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Class - Demospongiae

• have siliceous spicules, spongin, or both
• one freshwater family
• Spongillidae
• Has gemmules during the winter

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Gemmule
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Gemmule
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Figure 12.co
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Figure 12.08
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Figure 12.17
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Figure 12.17a
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Figure 12.17b
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Cliona
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Cliona
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Cliona killing a coral