Volume 2
Elementary text-book of zoology / by C. Claus ; translated and edited by Adam Sedgwick ; with the assistance of F.G. Heathcote.
- Carl Friedrich Wilhelm Claus
- Date:
- 1884-1885
Licence: Public Domain Mark
Credit: Elementary text-book of zoology / by C. Claus ; translated and edited by Adam Sedgwick ; with the assistance of F.G. Heathcote. Source: Wellcome Collection.
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![and it is only later, from the third year onwards, that they become females and produce ova. Moebius, on the contrary, asserts that the sperm is the later formed, and not until after the pregnant beast has got rid of her eggs. The re¬ production takes place especially in the months of June and July, at which time, in spite of their extraordinary fertility, the oysters must not be gathered. O. crista yaUi Chemn., in the Indian Ocean. Anemia cpliipp/mii L. Placnnn placenta L. Favn. Pectinilae. Scollops. Shell 6C]uivalved or unccjuivalvcd, but tolciuM} equisided, with straight hinge line ; often with fan-shaped ribs and bands, with single adductor muscle. The free and completely split mantle edges bear numerous tentacles, and often emerald green eyes in great number. The small foot often secretes byssus fibres for attachment. Some are attached by their arched shell valve (Spondylus), others swim about by rapidly opening and closing the shell (Preten)- Many are edible and are even more esteemed than Fig. 50i.—ihjtilm edulis (regne animal). 0, moutli j S, labial palps; foot; B, byssus secretion ; Brt gills ; A/, thickened edge of mantle. the oysters. Prrtru JacnTtccus b.. F. vm-rivivs L.. F.vaviu* b. Mcditeitanean. Spondylus yarderopus b. Lima gyiuimoxa I.am. Kam. Aviculidae. With oblique unequivalved shell of laminated texture and inner mother-of-pearl layer. They possess two adductor muscles, of which, however, the anterior is very small. Mantle completely open, hoot small, secreting byssus. Axicnla hirundo b.. Gulf ot lareut. Mrlrnyrina nmryari- t if era b., pearl mussel, inhabits especially the Indian and Persian Oceans, and also the Gulf of Mexico. Secretes pearls.* The internal layer of the shell is used in commerce as mother-of-pearl. Müllen* rubjn/'/*. Lam., Indian Ocean. Kam. Mytilidse (tig. 501). Mussels. Shell equivalved, covered with thick epidermis, with large posterior and small anterior muscle impressions. The tongue-shaped foot fastens itself by the byssus fibres which it secretes. Mantle more or less free except a short siphonal opening fringed at the edge. Pimm squamosa Gm., Mediterranean. Mytilu.< r/hilhi 1... edible mussel ot the North Sea and Baltic (fig. r><>4). Lithnlomvx dnctylus Sow., in the Mcditcr- * <•/'. Moebius, “ Die echten Perlen, etc.'’ Hamburg, 1857.](https://iiif.wellcomecollection.org/image/b29339388_0002_0030.jp2/full/800%2C/0/default.jpg)
