Department of Zoology at ANDC/Zoology Museum/Museum specimens/Platyhelminthes

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Phylum Platyhelminthes

Date & Time : 23, July 2024 14:38

General Characteristics of Platyhelminthes

Classification of Platyhelminthes

A Few Examples

1.Planaria dorotocephala

Common name- Dugesia

Habitat- freshwater species, found in ponds, lakes and springs.

Distribution- Cosmopolitan in distribution, found in India, Myanmar, U.K., U.S.A., and USSR.


  • Body- Body is elongated, cylindrical and dorsoflattened.
  • Body length- 2-15 mm.
  • Body color- brown to black.
  • Body division- It is divided into anterior head and posterior body.
  • Head- It is triangular containing auricles (ear like) and eyes or ocelli (semicircular, one pair). Auricles and eyes both are sensory structures.
  • Posterior body- it conmtains highly pointed end.
  • Digestive system- complete, consisting of mouth, pharynx, proboscis and intestine (branched).
  • Mouth- The mouth is situated in middle of the ventral surfaceand is surrounded by proboscis pore.
  • Intestine- It has three branches in which one is extending upwards and other two are extending backwards.
  • Genital pore- It is located posterior to the mouth.
  • Reproduction- It reproduces sexually or asexually. Regeneration also occurs.

2. Taenia solium

Common Name- Pork tapeworm.

Habit and habitat- It is the parasite in the intestine of man.

Distribution- it is found in India, China, Yogoslavia, and Germany.


  • Body- Body is about 4-5 meters in length.
  • Segmentation- it consists of about 700-900 segments.
  • Body division- It is differentiated intoscolex, neck and thenimmature, mature, gravid and malformed segments.
  • Mature segments- They contain fully developed hermaphrodite genital organs.
  • Scolex- It is adhesive in nature, consisting of four suckers and a rounded rostellum( surrounded by a double row of 28-32 hooks).
  • Life cycle- Life cycle of T. solium isindirect. It requires an intermediate host pig for development.
  • Diseases- It causes diseases like anaemia, secondary anaemia, eosinophilia, diarrhea, haemorrhage,abdominal pain and nausea etc.

3.Taenia saginata

Common name- Beef tapeworm.

Habit and habitat- It found in the posterior coils of the intestine.

Distribution- It found in India, China and Germany.


  • Body- it is about 4-6 meters in length.
  • Body color- whittish in color ( preserved).
  • Body segments- Body is divided into about 1000 segments.
  • Types of segments- There are four types of segments:-immature, mature, gravid and malformed segments.
  • Body division- Body is divided into scolex, neck and strobila (segments).
  • Scolex- It contain 4 suckers. But rostellum and hooks are absent.
  • Life cycle- Life cycle is indirect. Buffalo is intermediate host.
  • Diseases- It causes diarrhoea, nausea and insomnia and abdominal pain etc.

4.Fasciola hepatica

Common name- Sheep liver fluke.

Habit and habitat- It is a pathogenic parasite in the liver and bilary passage.

Distribution- Cosmopolitan distribution. It found in sheep raising areas like India, U.S.A., Cuba and Syria etc.


  • Body- It has beef like and dorso-ventrally flattened body.
  • Body length- 18-50 mm in length.
  • Mouth- Mouth is small and ventrally situated at anterior extremity.
  • Suckers- There are two types of suckers naming oral and ventral sucker.
  • Oral sucker- It surrounds the mouth and located at the anterior extremity.
  • Ventral sucker- It is also called acetabulum ( adhesive in nature) and is located a little behind to the mouth.
  • Pores- gonopore and excretory pore. 

             (1)Gonopore is locatedbetween oral and ventral suckers

             (2)Excretory pore is located at posterior extremity

  • Cephalic cone- Anterior end consists of a conical projection. This is called cephalic cone.
  • Hermaphrodite.
  • Digestive system- It consists of mouth, oral sucker, pharynx, oesophagus and bifid intestine.
  • Life cycle- Indirect and is completed in two hosts sheep and snail.



  • Digestive tract- consist of simple pharynx.

  • Excretory system- consist of single protonephredia (median).

  • Nervous system- 4 pairs of longitudinal nerve cords and a statocyst.

  • Reproduction- asexual by transverse fission.

  • Habitat- freshwater.


Habitat- exclusively marine form, lives under stones among algae.


  • Body is small and ventrally curved.

  • Anterior end contain frontal glands (many in number), eyes (one pair),  a single statocyst and mouth (ventrally situated).

  • intestines are absent.

  • excretory system is absent.