A Manual of Conchology / According to the System Laid Down by Lamarck, with the Late Improvements by De Blainville. Exemplified and Arranged for the Use of Students.

by Thomas Wyatt

Species oval, sub-auriculated; cardinal tooth short, not lamellar or sub-striated.

U. sub-orbiculata. The sub-orbicular Unio.

Species round or almost round; cardinal tooth compressed, elongated, and often lamellar.

2. Hyria. Two species.

Easily distinguished from the Unio by a compound cardinal tooth, which slopes in an inclined position towards the posterior side. They are more found in lakes than in rivers.

Shell solid, pearly, equivalve, obliquely triangular, auriculated; base truncated and straight; hinge with two projecting teeth; the cardinal divided into numerous divergent parts; anterior ones smaller, the others long and lamellar.

Hyria avicularis.

Hyria corrugata.

H. avicularis. The little bird Hyria. Pl. [5], fig. 4.

Umbones smooth and polished; ears large, with pointed terminations; finely striated; interior pearly, exterior of a rich reddish golden-yellow colour; covered with a greenish brown epidermis.