Echinoida

Purple sea urchin ( Strongylocentrotus purpuratus )

• Echinidae
• Drilling and pencil sea urchin ( Echinometridae )
• Parasaleniidae
• Strongylocentrotidae

For of the genuine sea urchin ( Echinoida ) the most common and best-known sea urchin coasts of Europe, such as the edible sea urchin ( Echinus esculentus ) and the stone sea urchins include ( Paracentrotus lividus ) from the family of Echinidae and the species-rich genus Strongylocentrotus from the family of Strongylocentrotidae.

Features

The Real urchins are morphologically to the "regular" sea urchins ( formerly known as Regularia ). For this one or five-star, radially symmetrical calcareous skeleton and an apple-shaped figure are characteristic. The mouth is at the bottom surrounded by a membranous mouth field. The anal opening is located in the center of the top. In the middle of the mouth field are the tips of the five teeth, which are anchored in a complicated jaw structure that was called because of its shape by Pliny the Elder " lantern of Aristotle ". The Echinoida the cutouts in the upward widening jaw skeleton bridged by Barrettes as in the order of Temnopleuroida. The Echinoida but have no special grooves on the shell surface and the gill slits are indistinct and not as deeply cut as in the Temnopleuroida.