Sub-topic #2: Hydra LS and CS

• HYDRA LS AND CS:

  Outer - epidermis

  Inner - gastrodermis

  Mesoglea - thin section in between that is noncellular and jelly-like
• Dominant form in Hydra: polyp form
• Dominant form in Trachilina: Medusa form
• Mesoglea is thicker in Hydrozoan medusa because it helps in floatation, but thinner in Hydrozoan polyp as it is only sessile.