Study Called Parazoology.
Grant termed Porifera.
Ellis established animal nature of sponges and
Wilson gave regeneration in Sponges.
Solitary-------------------->Sycon
Colonial-------------------->Leucosolenia
Called sponges and republic of cells.
Unique feature of porifera is canal system.
Sponges are filter feeder.
Poriferans are protogynous(female mature before
male) or Hermaphrodite.
Development indirect.
Porifera are invertebrates without neurons.
Water current through the body of sponges is
maintained by Choanocytes.
Diploblastic ------------------->
Outer pinacoderm and inner choanoderm
Pinacoderm has multi-nucleated flattened Pinacocytes
and uninucleated tubular Porocytes.
Choanoderm have flagellated choanocytes.
Between pinacoderma and choanoderm is
mesenchyme/mesohyl containing collagen fiber, spicules and amoebocytes.
Amoebocytes(wandering cells)
- Archaeocyte-largest,
totipotent cell
- Trophocyte- Nurse cell, supply nutrient to
developing cells
- Collencytes-uninucleated,
secrete collage fibre
- Scleroblast- Secrete spicules
and sponging fibres
- Germ cell, gland cell,
chromocyte, etc.
Canal system
- Ascon(Leucosolenia)
- Sycon(Sycon)
- Leucon/Rhadon
type(Euplectella, hyalonema, demospongia)
Ascon type path of water/food.
Dermal ostia------------>Gastral
ostia-------------->Spongocoel----------------->Osculum
Digestion of food partially in choanocyte and
partially in wandering amoebocyte.
Reproduction
- asexual--------->Fragmentation,
gemmule or buds
- Sexual----------> by ova
and sperm
Larval forms are
Amphiblastula-hollow-eg. Sycon
Parenchymula-Solid-eg.Leucosolenia
Sponges classes
- Calcarea- ascon/sycon(eg.
Sycon/Leucosolenia)
- Hexactinellida-sycon/leucon-eg.Euplectella,
Hyalonema
- Demospongia-Leucon(eg.
Spongilla, Euspongia)
- Euspongia--------->Bath
sponge(sponging
fibres left after drying)
- Cliona----------->Boring
sponge(harmful to
pearl/oyster industry)
- Euplectella---------->Venous
flower basket