Zoological Illustrations, Second Series, Volume 1 / or, Original Figures and Descriptions of New, Rare, or Interesting Animals

by William Swainson

ANODON areolatus.

Areolated Horse Mussel.

Generic Character.

See [Unio, Pl. 1.]
(Anodon. Iridina. Dipsus. Auct.)

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Specific Character.

Shell transversely oval, not winged, umbones small, ventricose, not touching; with a short undulated projection of the hinge margin in one valve, and a corresponding concavity in the other; both placed beneath the umbones.

The principal character of Anodon, rests on the absence of teeth; the A. anatinus, common to our rivers and ponds, being taken as the type of the group. But, as Nature steps progressively, in her departure from one form, and in her advance to another, so among the Anodons we find several shells, which do not strictly exhibit the typical character; and these we shall briefly notice.