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Humans have a bilateral symmetry, while the moon jellyfish has a radial symmetry. |
Cnidarians do not possess anything that can be called a
brain. This implies that they are insensitive and devoid of the power
of decision. Nerve impulses are transplanted through the body like ripples
on water.
Cnidarians are devoid of well developed sensory organs.
There are very few that can see and probably none that can hear. Moon
jellyfish can however experience their surroundings with several senses.
The cnidarian group incorporates about 270 specie in Swedish
waters and about 9 000 specie globally. Often they are sub-divided
into several groups, the hydrozoas,
the jellyfish and the anthozoas.
Read about the different
cnidarians!!
Page 4 of 13 |