Star Ascidian
Botryllus schloserri

Star ascidians are one of the most attractive finds in a rock pool.

Found covering rocks and sometimes seaweeds, they appear like a layer of coloured jelly with pressed flowers inside.

They are not a single organism but a collection of sea squirts living together.

Each 'petal' is a single squirt which grops with others to form a 'flower'. Each squirt has a syphon which sucks in sea water so that the organisam can extract oxygen and food. 

In the centre of the 'flower' is a shared outflow syphon through which the water is released into the sea after the nutrition has been extracted from it. It is not unlike a group of friends all going to different restaurants but using the same toilet!

Star asidian on wrack

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