Ordo Arcoida

Stoliczka, 1871

Mostly solid and equivalve shells with a row of small teeth in each valve and with the beaks apart exposing a cardinal area. Most species inequilateral with the beaks in the anterior half; one species, Glycymeris glycymeris , has central beaks and is perfectly equilateral. Ligament external. Adductor muscle scars about equal; no pallial sinus. Some species live low in the intertidal zone nestling under rocks and stones or clustered in nooks and crevices, whilst others burrow into sand and mud just offshore.

Source: Tebble, 1966.

The following subtaxa of this order occur in the region:

Family Glycymerididae
Genus Glycymeris
Glycymeris glycymeris
Family Noetidae
Genus Striarca
Striarca lactea
Family Arcidae
Genus Bathyarca
Bathyarca pectunculoides
Genus Arca
Arca nodulosa
Arca tetragona

%LABEL% (%SOURCE%)