User:Pooja srivastava/E-Museum/Coelentrata/Some Common Examples

Metridium

SCIENTIFIC NAME-

Metridium

COMMON NAME-

Sea anemone or Plumose anemons

DISTRIBUTION-

Found on the Atlantic Coast, Northen Pacific coast and Europe.

HABITAT-

It is marine in nature and found attached to the rocks and solid objects from tide pools to a depth of 90 fathoms.

IDENTIFYING FEATURES-

• Body is cylindrical and divisiblle into 3 distinct reagions, pedal disc, column and oral disc.
• The body size may vary from few centimeters to 1 meter.
  
• Pedal disc (foot) helps in attachment with substratum.
• Column is diffrentiated into two portions-Capitulum(thin walled ) and Scapus(thick walled).The wall of scapus is perforated by small openings called cinclides.
• Mouth is surrounded by numeros tentacles.
  

GENERAL CHARACTERS-

• Mouth opens into gastrovascular cavity via a short gullet.
• Sea anemones are predaceous, immobilizing their prey with the aid of specialized stinging cells called nematocysts.
  
• Sea anemones feed on small planktons.
  
• Sexes are separate.Gonads are present on mesentries.

Hydra

'SCIENTIFIC NAME-

Hydra

GEOGRAPHICAL DISTRIBUTION-

Cosmopolitan ,but most common in India ,Canada and U.S.A.

HABITAT-

It is freshwater solitary animal found attached to some objects in ponds , lakes and streams.

IDENTIFYING FEATURES-

Hydra is elongated , cylindrical and measures 1-3cm in length.
Proximal end of body is known as BASAL DISC or foot, and is used for locomotion.
The free distal end bears mouth situated on a conical elevation called the HYPOSTOME.
Hypostome is encircled by 6-10 tentacles which are finger like ,hollow projection provided with nematocytes.
Body wall is DIPLOBLASTIC.

COMMON CHARACTERS

Digestive cavity or GASTROVASCULAR CAVITY is enclosed by body wall.
Reproduction by both sexual and asexual.
Gonads appear as buds on the sides of body. Testes lie near the oral endand ovaries near the base.

TUBULARIA

SCIENTIFIC NAME-

Tubularia

GEOGRAPHICAL DISTRIBUTION-

Found in Europe , california

HABITAT-

Marine , also found attached to piles in shallow water.

IDENTIFYING FEATURES-

The colony of Tubularia consists of tufts of irregularly branched stems bearing hydranths arising from hydrorhiza.
Hydranths have long stalk and two sets of solid filiform tentacles.
Hydranths or polyps have flower like appearance.
Stem contains perisarc and coenosarc and is transparent.

COMMON CHARACTERS-

Gonophores arise as hollow branches from the body of the hydranth between two sets of tentacles.
Colony is dioceous.
Gonophores produce medusae.
Reproduction both sexual and asexual.

SERTULARIA

SCIENTIFIC NAME-

Sertularia

GEOGRAPHICAL DISTRIBUTION-

Cosmoplitan

HABITAT-

Marine hydroid found attached to the rocks and stones.

IDENTIFYING FEATURES-

The colony consists of HYDRORHIZA which gives rise to vertical stems.
Vertical stems bears hydrotheca that arise from internodes in pair and lies opposite to each other.
The mouth of each hydrotheca is covered by a pair of operculum.

COMMON CHARACTERS-

The gonangia are sessile ,oval and larger than hydrotheca and also bears blastostyles.
Blastostyles are reproductive zooids which come out from the mouth of gonangia.

OBELIA

SCIENTIFIC NAME-

Obelia

Geographical dtstribution-

It is found from Arctic region to the Gulf of Mexico and the pacific coast , and from Southern California to Oregon.

Habitat-

IT is colonial ,marine , sedentary hydrozoan zzophyte found attached on piles , rocks and see weeds in shallow water.

Identifying features-

It is a colonial hydroid.
The colony consists of basal horizontal portion , the hydrorhiza which is attached with the substratum and number of vertical branches knwon as hydrocauli arising from hydrorhiza.
The colony is trimorphic having three types of zooids, e.g,,hydranth , blastostyle and medusa.
Hydranth or polyp has a cylindrical body attahed to the axis of the hydrocaulus by its proximal end and free at its distal end.
It is covered by cup shaped hydrotheca . It is nutritive zooid of colony.
The hypostome is surrounded by a number of solid tentacles provided with nematocytes.
Blastostyle or reproductive zooid is cup shaped without mouth and tentacles.
It is enclosed by covering, gonotheca.
It gives rise to buds which later become flattened and develope into new medusae.
Medusa is bell- shaped with a concave and convex side. It contains marginal tentacles, four radial canals , a ring canal four gonads born on the radial canals and hanging central manubrium on the concave side.
The medusae are free swimming.
Life history of obelia exhibit an alternation of generation.

Millepora

SCIENTIFIC NAME-

Millepora

Geographical distribution-

Found in West Indies and U.S.A.

Habitat-

Colonial marine coral found in shallow water.

Identifying features-

• Colony consists of branching calcareous growths up to 30-60cm in height and is white or yellowish in colour.
• Two types of pores are found in surface of the colony-
• 1. large gastropores
• 2. small dactylopores
• Colony have 2 kinds of zooids-
  

1.Gastrozooids-. shorter containing mouth and tentacles.

                      .  Protrude through gastropores .

                        . nutritive in function.

2.Dactylozooids-longer and hollow containing tentacles.

                      .   Mouth is absent.

                      .   These are enclosed by dactylopores

                      .    Protective in function.

                      .  It also contains calcareous rounded chambers called ampullae.

                       . Medusae buds of from ampullae . They do not contain mouth and tentacles.