PHYLUM: COELENTERATA
GENERAL CHARACTERS
1. These are aquatic animals; some are fresh water while some are marine water.
2. They may be solitary, colonial, and sedentary or free swimming.
3. They possess a cavity called coelenteron and are diploblastic having non cellular mesoglea.
4. The animals are radially symmetrical and appear in two forms polyp and medusa.
5. Digestion both extracellular and intra.
6. Special types of cells i.e. stinging cells/ nematocysts are present.
7. Reproduction sexual as well as asexual
8. This phylum is divided in to following three classes
9. Phylum — Hydrozoa, Scyphozoa, and Anthozoa.
HYDRA
Phylum; Coelenterata Coelomic enteron
Class: Hydrozoa Polyps without stomodaeum
Order : Hydroida Polyp stage is pre-dominant.
Genus: Hydra
Species vulgaris
· CHARACTERS :
1. Found in freshwater in pond lakes and streams
2. Attached to the substratum with it base
3. Body is cylindrical.
4. Mouth present on anterior end on hypostome.
5. Mouth is surrounded by 6 to 10 tentacles.
6. Nematocysts are the organs of offence and defense.
7. Hermaphrodite animal.
8. Reproduction by sexual and asexual.
OBELIA
Phylum; Coelenterata Coelomic enteron
Class: Hydrozoa Polyps without stomodaeum
Order : Hydroida Polyp stage is pre-dominant.
Genus: Obelia
Species geniculata
· CHARACTERS:
1. Found in marine water.
2. Colonial animal.
3. Polyp or hydranth is the nutritive zoids of colony.
4. Tentacles are solid.
5. Polyps reproduces asexually by budding.
6. Sexual reproduction by Medusa.
JELLY FISH /AURELIA:
Phylum; Coelenterata Coelomic enteron
Class : Scyphozoa Medusa stage dominant and polyp stage reduced or absent.
Order : Saemaeostomae Flat disc like umbrella.
Genus : Aurelia
· CHARACTERS:
- Commonly called as jelly fish.
- Found in marine water.
- Convex aboral surface (Umbrellar surface)
- concave oral surface (Ex-umbrellar surface. )
5. Mouth is present on ex-umbrelar surface..
- Presence of 4 tentacles.
- Present of 4 oral arms.
- Tentacles with nematocyst as organ of offence and defense.
- Sexes are separate.
SEA ANEMONE (METRIDIUM)
Phylum; Coelenterata Coelomic enteron
Class - Anthozoa Only polypoid generation, sedentary, solitary or colonial.
Order - Actiniaria Without skeleton, with mesenteries or septa in multiple of six,
Type - Metridium. Basal disc present.
CHARACTERS
- It is marine coelenterate.
- It has usually brownish or pinkish colour.
- Body is short, cylindrical, radially symmetrical
- Body is divisible into pedal disc, column and oral disc
- Pedal disc or base is attached to substratum firmly.
- The column forms major part of the body.
- The column is divisible into an upper, short, thin walled capitulum and lower, thick walled scapus.
- The capitulum and the scapus are separated by a prominent fold called as collar.
- The oral disc is surrounded by several marginal tentacles around the mouth.
Dr, Vidhin Kamble
Department of Zoology
Sangola College, Sangola
