Ctenophora General Characteristics and Classification | 100% Free Biology Notes

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Ctenophora General Characteristics

• Habit & Habitat – Exclusively marine and mostly solitary
• Ctenophora are also known as comb jellies due to presence of external rows of ciliated comb plates
• Ctenophora composed of two layers of tissue known as ectoderm and endoderm with non cellular layer called mesoglea in between
• Epidermis is made of Sensory cells, mucus secreting cells, lasso cells and nerve cells
• Gastrodermis is layered tissue with Long storage cells, germ cells and photo cells
• Tentacles are present. Solid and adhesive cells are present called lasso cells which help in catching prey
• Sexes are not separate
• Reproduction takes place by sexual means
• Fertilization is external
• Development is indirect type
• Immature ciliated stage larva called cydippid larva

Classification of Ctenophora

Class 1. Tentaculata

• The body is rounded or oval o ribbon like
• Two long aboral tentacles are present
• Mouth narrow and pharynx small
• E.g. Hormiphora (The Sea Walnut), Pleurobrachia (The Sea gooseberry), Cestum (The Venus’ Girdle).

Class 1. Nuda

• The body is large and conical
• Without tentacles
• Wide mouth and large pharynx
• E.g. Beroe (Swimming eye of cat)