Echinocyamidae

Echinocyamidae; Temporal range: 9–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Miocene to Recent
	Echinocyamus pusillus
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Echinoidea
Order:	Clypeasteroida
Suborder:	Scutellina
Infraorder:	Laganiformes
Family:	Echinocyamidae; Lambert & Thiéry, 1914
Genera
	Echinocyamus; †Leniechinus; Mortonia;

Echinocyamidae is a family of sand dollars. They are found mostly off the coast of Britain and Ireland and the North Sea, with scattered populations in the tropics.^[1]^[2]^[3]

Description

They are Laganiformes with:

simple radial internal buttresses along interambulacral margins;
periproct close to peristome and opening bounded by first and second paired post-basicoronal interambulacral plates
interambulacral zones terminating adaptively in one or two single small plates
basicoronal circlet small and unspecialized
no food grooves

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