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MONTESSORI ZOOLOGY : External Parts of Platyhelminthes

The Platyhelminth

Platyhelminths are worm-like unsegmented 
animals. They have a fully developed 
digestive tract with a hole for excretion.


The body of the platyhelminth is soft
and slender. The body is tapered and
hasa triangular "head" at one end.


Some platyhelminthes move with the help 
of cilia on the ventral surface (flatworms).
Other platyhelminthes move with the
help of cuticle (flukes and tapeworms). All 
platyhelminthes have internal muscles as well. 


A pair of eyespots on the dorsal side of the 
platyhelminth react to light, but do not form images. 


 The mouth of the platyhelminth is near the
middle of the body on the ventral surface.
A tube shaped pharynx can be extended
through the mouth to capture food.

Canal Openings

 Waste exists through canal openings on
the dorsal surface of the platyhelminth.
The canal openings are difficult
to see with the naked eye.


 -Pinegreenwoods Montessori
Montessori Zoology