1. The phylum Cnidaria includes over 9,000 species of mostly marine animals classified into four classes: Hydrozoa, Scyphozoa, Anthozoa, and Cubozoa. 2. They are commonly called "stingers" because their tentacles contain stinging cells called cnidocytes that are used for defense, feeding, and attachment. 3. The classes differ in whether they are marine or freshwater, whether the polyp or medusa form is more prominent, and details of their gastrovascular cavity, mesogloea, and gonad placement. Examples across the classes include Hydra, jellyfish, sea anemones, corals, and box jellyfish

1. TOPIC : CLASSIFICATION OF PHYLUM
CNIDARIA UPTO CLASS

2. CLASSIFICATION OF PHYLUM CNIDARIA
Class Hydrozoa
• Fresh water as well as marine.
• polyyp and medusa often show polymorphism and
metagenesis.
• Mesogloea is acellular.
• Gastrovascular cavity is undivided.Gonads are
ectodermal and shed.

3. • Gametetesgametes directly surrounding water into the surrounding water.
• Cnidoblast is present only in epidermis.
• Examples, Hydra (fresh water polyp), Physalia (Portuguese man of war;
neurotoxic, gas gland .

4. FIGURE OF HYDRA AND PHYSALIA

5. CLASSIFICATION OF PHYLUM CNIDARIA UPTO
CLASS
• It include over 9,000 species
• These are mostly marine.
• Important in coral reef.
• These also called“the stingers” because their tentacles
• are present near the mouth bearing stinging cells called
Cnidoblast or cnidocytes composed of nematocysts.

6. CHARACTERISTICS OF PHYLUM CNIDARIA
• Radial or Biradial symmetry
• Tissue level organization and Diploblastic.
• Mesoglia is present.
• Gastrovascular cavity.
• Nervous system in the form of nerve net.
• Cnidocytes for defense , feeding and attachment.
• Oral and Aboral end.

7. • Respond to stimuli from all directions
• Examfishples: Hydra , Obelia, jell fish etc
•

8. • Class Scyphozoa:
• Extensively marin
• Medusa form is most common.
• Mesoglia is thick, gelatinous and contain cells.
• Gastrovacular cavity is undivided.
• Gonades are endodermal and shed the gametes into digestive track when
escape through mouth.

9. • Cnidoblast is present in epidermis and
gastroderm.
• Example:AureIia( jelly fish,moon
fish),larva
• : Ephyra etc.
• fig :
Aurelia

10. • (3) Anthozoa (Actinozoa)
• Exclusively Marine.
• Only polyp form
• .Mesogloea contains cells and fibers.
• Gastrovascular cavity has compartments, i.e., mesenteries.
• Gonads are endodermal and shed gamete into digestive tract escape via mouth.
•
•

11. • .Cnidoblast is present in epidermis and gastrodermis.
• This class has two types of animals: Anemones (Skeleton absent) Adamisa (Sea
anemone) and Corals (CaCO3 skeleton) – Pennautula (Sea pen), Gorgonia (Sea
fan).Gastrodermal in origin; medusa cuboidal in arine, Chirones, Fleckeri,
charybdea.
• fig: Sea Anemone

12. • 4) Class Cubozoa (ku”bo-zo’ah)
• Medusa prominent in the life history, polyp small: gametes gastrodermal in origin,
medusa cuboidal in shape with tentacles that hang from each corner of the bell:
marine, Chirones, Fleckeri, charybdea.
• fig:charybdea