Copy 1

The Linnaean system of conchology ... / By John Mawe.

  • John Mawe
Date:
1823
Catalogue details

Licence: Public Domain Mark

Credit: The Linnaean system of conchology ... / By John Mawe. Source: Wellcome Collection.

    77/300 (page 37)
    DONAX.—WEDGE-SHELL. DESCRIPTION OF PLATE IX. Drv. I.—Fig. 1. D. scortum. Duy. Il.—Fig. 4. D.denticulata. Drv. I1].—Fig. 3. D. madagascariensis. Fig. 5. D. trunculus. Diy. [V.—Fig. 2. D. scripta. Fig. 6. D. elongata. Fig. 7. D. stultorum. Shell bivalve, with generally a crenulated margin, the frontal margin very obtuse; hinge with two teeth, anda single marginal one placed a little behind, rarely double or triple. THE principal characteristic of the Donax is deriv- ed from its form, which (throughout its twenty-four species) is similar to that of a wedge, being very broad and thick at one extremity, and gradually tapering to- wards the other. The margin, which is generally of a deep color, is almost invariably crenulated or beset with small contiguous teeth; and the frontal margin is generally very obtuse: the anterior slope not unfre- quently gapes, and has a ligament situated near the fissure, which prevents the two valves from sepa- rating, when the animal has occasion to open them. Some specimens of this genus, in their external ap- pearance, bear a strong resemblance to the species of the Venus; but the examination of the hinge will always determine to which of the genera the shell belongs. The Donax presents so great a diversity in external character, that it has occasioned the genus to be sepa- rated into five divisions. In the first, the species ex- hibit a rough and decussated surface, caused by crowd-