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Euechinoidea

Euechinoidea (class Echinoidea) Sub-class of sea-urchins in which the normally rigid test is composed of five ambulacra and five interambulacra, each made up of two columns of plates. The subclass includes both regular types of echinoid (e.g. Hemicidaris) and irregular types (e.g. Clypeus, Micraster). They first appeared in the Upper Triassic.

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"Euechinoidea." A Dictionary of Earth Sciences. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"Euechinoidea." A Dictionary of Earth Sciences. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/euechinoidea

"Euechinoidea." A Dictionary of Earth Sciences. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/euechinoidea

Euechinoidea

Euechinoidea (subphylum Echinozoa, class Echinoidea) A subclass of sea urchins in which the normally rigid test is composed of ambulacra and interambulacra, made up of two columns of plates. Spheridia are present. The subclass includes both regular and irregular types of echinoid. They first appeared in the Upper Triassic.

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Pick a style below, and copy the text for your bibliography.

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"Euechinoidea." A Dictionary of Zoology. . Encyclopedia.com. 20 Aug. 2017 <http://www.encyclopedia.com>.

"Euechinoidea." A Dictionary of Zoology. . Encyclopedia.com. (August 20, 2017). http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/euechinoidea-0

"Euechinoidea." A Dictionary of Zoology. . Retrieved August 20, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/euechinoidea-0