Sea urchin

Wikispecies has an entry on:

Echinoidea

Alive

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  Paracentrotus lividus
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  Echinus Melo (water melon urchin) Alghero Sardinia
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  Arbacia lixula Croatia
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  Diadema antillarum
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  Strongylocentrotus purpuratus (Purple sea urchin)
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Test (Skeleton)

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   Colobocentrotus atratus
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    Echinodiscus tenuissimus
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  Echinus esculentus
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    Paracentrotus lividus

Eggs

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  Sea urchin eggs
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  Sea urchin eggs
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  Sea urchin roe from Alghero Sardinia

Fossil

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   Acrosalenia hemicidaroides
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   Micraster leskei

Illustration

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  Pluteus
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  From "On the Genesis of Species"
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  Pedicellariae enlarged.

Video

• Time-lapse video of 16-cell purple urchin embryo

Divers

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  Sear Urching fishing net in Alghero Sardinia