Phylum: Platyhelminthes, Phylum: Nematoda, Phylum: Annelida

Phylum: Platyhelminthes,

Phylum: Nematoda,

Phylum: Annelida.

Prepared by T. Madhavan & K. Chandrasekaran, Lecturers in Zoology, Directorate of School Education., Pondicherry.

An Illustration for the students who aspire for medical studies.

PLATYHELMINTHES

• They are multi-cellular, triplo-blastic and bilateral symmetrical.

• These are acoelomate.

• Excretion is effected by flame cells.

• The body is flattened structure.

• These worm are mostly hermophrodites.

• Most of the members are parasites.



TURBELLARIA TREMATODA CESTODA

PLANARIA LIVER FLUKE TAPE WORM









• They are round worms.

• The body is narrow and pointed at both ends.

• No segmentation.

• They body is covered by cuticle.

• They are pseudocoelomate.

• Reproduction is sexual method.

• Sexes are separate.• Example : Ascaris.





ANNELIDA• These are worm like animals.• The body is divided into number of segments.• All the segments have identical arrangements of

organs . This is called metamerism.• The body is protected by a cuticle.• Excretion is effected by Nephridia.• Presence of central nervous system.• These are hermaphrodite.• The life cycle shows the larval stage called

trochophore.



POLYCHAETA OLIGOCHAETA HIRUDINEA

NEREIS EARTHWORM LEECH



Marine worm

The body is divided in to number of segments.

Each segment has a pair of lateral projection called Parapodia.

Parapodia are used in locomotion.

They have a distinct head.



NEREIS





LEECH

• These are blood suckers and ectoparasites.

• The body has 33 segments and shows anterior and posterior suckers.

• Sangivours.





End

Documents

Phylum: Platyhelminthes, Phylum: Nematoda, Phylum: Annelida