. Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . Fig. 28.—Pirula sp. (a), with broad flattened foot, living on loose bottom, contrasted with Rostellaria curia, (b), with narrow foot, from solid bottom at 45-m. depth. After Hornell. wise sharks and rays for the most part lie on the surface, protected by their spiny coat and rendered indistinct by their coloration. Among the squids, Sepia tends to keep itself slightly embedded in sand or mud, adjusting its coloration to that of the bottom material. The number of forms living on
. Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . Fig. 28.—Pirula sp. (a), with broad flattened foot, living on loose bottom, contrasted with Rostellaria curia, (b), with narrow foot, from solid bottom at 45-m. depth. After Hornell. wise sharks and rays for the most part lie on the surface, protected by their spiny coat and rendered indistinct by their coloration. Among the squids, Sepia tends to keep itself slightly embedded in sand or mud, adjusting its coloration to that of the bottom material. The number of forms living on the surface of the sand is small in contrast to the hidden inhabitants of sand bottom. Numerous brittle stars and some starfishes have this habit, and in them the tube feet are rounded instead of ending in a sucking disk. A number of carnivorous snails, such as Buccinum and Nassa, creep over the surface of the sand. Such snails, on account of the looseness of the bottom, require a broad foot, a contrast with snails in rocky habitats, especially in quiet water, which require only a small foot (Fig. 28). A number of crabs, such as Portunus, Hyas, and Inachus, live on the sand surface, and this is the typical habitat of the hermit crabs, which often occur in great numbers.
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Keywords: ., bookcentury1900, bookcollectionbiodive, booksubjectanimalecology
