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
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