The Echinoid Directory

Glossary terms beginning with: I

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inner (fasciole)

A fasciole band that encircles the adapical part of the anterior ambulacrum but does not enclose the petals, passing closer to the apical disc than any well-developed petal pore-pairs. (show image)

insert

An arrangement of apical disc plates in which the ocular plates (white) are separated from the periproct opening by genital plates (purple) (dicyclic plating). (show image)

interambulacra

pleural of interambulacrum (show image)

interambulacrum (-al)

Of or pertaining to the plates separating ambulacral zones in the corona and which are usually biserially arranged. (show image)

interporal partition

The calcite bar that separates the two pores in a pore-pair. (show image)

interradial

at or towards the centre of the interambulacral zone (direction) (show image)

interradius

Suture separating the two columns of interambulacral plates (show image)

isopore

An ambulacral pore-pair connecting tube-foot and internal water vessel composed of a pair of similar-sized pores.