The sea-shore / [P. Martin Duncan].

  • Duncan, P. Martin (Peter Martin), 1821-1891.
Date:
1879
Catalogue details

Licence: Public Domain Mark

Credit: The sea-shore / [P. Martin Duncan]. Source: Wellcome Collection.

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    many shores; and thus some kinds of creatures which now enliven the rock-pools and sands are found also in the Mediterranean Sea and on the distant coasts of Iceland, Greenland, and North America. Even British seaweeds have got to Australia. Living things, which can only live on the shores, and which cannot traverse the abyss of the ocean, are thus transported from land to land by emigration, along altering, forming, rising, and sinking shores. The seaward limit of the shore is strictly that line which marks the greatest going out of the tide. Beyond this the water increases in depth, more or less suddenly, and the floor of the sea there is con- stantly submerged, it being very rarely exposed to the air during some low spring tides. Different animals and seaweeds live in this part of the sea, and they, as a whole, cannot struggle against the repeated changes of depth and the successive exposures to air which appear to invigorate the true animals and plants of the shore. Nevertheless, some of the shore crea- tures live in the depths beyond, and some of the dwellers in the sea beyond the shore, often come upon it. Moreover, some animals which are never seen alive on the shore when mature, but which swim freely in the ocean, commence their life on the shore under very different shapes. Many birds frequent the shore occasionally, and gulls and cormorants are there constantly on the look-out for food and prey, having come from their distant homes and from the open sea, their usual hunting-ground. Fish swim over the shore at high tides, and stragglers are often left be- hind ; but they are not necessarily of the same kind as