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Date & Time : 29, April 2024 14:19
T.S. of Sycon
Identifying Features
- Body wall is diploblastic composed of pinacoderm and choanoderm with a middle layer of mesenchyme.
- Pinacoderm is made of flat cells - pinaocytes.
- Mesenchyme contains calcareous spicules and amoeboid cells such as trophocytes, thesocytes, collencytes and archeocytes. It is gelatinous in nature.
- Choanoderm contains single layer of large flagellated collared cells (choanocytes) which also forms the lining of radial canals.
- Water enters body through deermal ostia into the incurrent canal which are connected to radial canals by prosopyles.
- Each radial canal opens into central spongocoel by an apopyle from where water exits through osculum.
- Canal system is syconoid type.
Route of Water
Water (enters) ⇒ ostia ⇒ incurrent canal ⇒ radial canals through prosopyles ⇒ excurrent canal through apopyle ⇒ spongocoel through gastral ostium ⇒ leaves spongocoel by osculum.
L.S. of Sycon
Identifying Features
- Body wall is diploblastic. It consists of pinacoderm and choanoderm enclosing mesenchyme in between.
- Pinacoderm is made up of pinacocytes that covers the entire outer surface.
- Mesenchyme is composed of various kinds of amoebocytes, gelatinous transparent matrix and spicules.
- Choanoderm or gastral epithelium consists of single layer of flagellated collared cells known as choanocytes which also forms the lining of radial canals.
- Spongocoel is lined by flat pinacocytes.
Route of Water
Water (enters) ⇒ ostia ⇒ incurrent canal ⇒ radial canals through prosopyles ⇒ excurrent canal through apopyle ⇒ spongocoel through gastral ostium ⇒ leaves spongocoel by osculum.
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