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.

    32/300 page 6
    other species possess the intermediate gradations of number, as far as twenty-four, which is not un- frequent in the L. pollicipes.—The valves, of what- ever number they consist, are variously diversified with striz, ridges, and grooves. The strie are mostly transverse; the ridges, on the contrary, are longitudinal, and not uncommonly beset with rough projections and acute spines, as in the L. spinosa. The valves which compose the operculum, or lid, often vary in their number and shape; in some they only consist of two; in others, of three or four; and sometimes of afar greater number. They are usually attached to a ligament, and occasionally present an acute form, while in other species they are perfectly obtuse. The color also differs considerably, though the most usual is of a bluish, purplish, or reddish cast; some are variegated with black and green, and others are greyish-white, as the L. mitella, &c. The Lepades are never found detached, but.always fixed by the base or stalk to otherbodies; they adhere in clusters to rocks, and often form groups on shells, loose stones, anchors, &c.; they are also found on marine ani- mals, as the whale andthe turtle. They also affix them- selves to ships, and, though at first invisible, so rapid is their increase in magnitude and number, that the veloci- ty of a vessel is considerably impeded by them. This seems to imply that the animal exists in the sea in the state of animalcula. The interior of some species of this genus is a hollow tube, but in others it is divided into separate compart-
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