Marvels of the Universe 979 
like a British soldier with his back to the wall, he can defy a dozen adversaries. If there is no rock 
handy, he can bury himself quickly in sand or gravel by the same means; then by packing his 
bristly limbs close to his body, they will act as a rough filter for the water that is being drawn under 
the edges of his upper shell to keep his gills supplied. 
In the common Shore Crab (illustrated on page 884), which is more given, when at rest, to burying 
itself in the sandy shore, with its eyes and antenne exposed, the front edge of the shell on each side 
of the eyes is cut into five tooth-like lobes to assist in this same object—the filtering off of overlying 
sand whilst allowing water to pass between the teeth, and beside the folded limbs to the gill-opening 
below. The hinder pair of legs have the last joint flattened out, and in the Shore Crab’s very near 
relations will be found illustrations of the way in which this flattening has been increased to fit the 
limb for use as a paddle. In the Velvet Fiddler Swimming Crab, shown on page 985, the last two 
joints have been expanded to a far greater extent, in order to fit the crab for swimming. This 
process reaches a climax in Henslow’s Swimming Crab, which has had the entire shell made thin 
and light, to enable the crab to mount to the surface-water and pursue schools of fish upon which 
it preys. 
These locomotive limbs of the crabs are variously manipulated by Nature to serve different 
purposes. In some of the Spider Crabs they are drawn out to a remarkable length and fineness, 
to enable them to climb among the more delicate seaweeds and hydroids. An example of this 
treatment is given on page 978, where the Long-legged Spider Crab is shown with limbs five or six 
times the length of the body. Just as the long, slender legs of the Garden Spider enable it to climb 
over the rigging of its own snare and to run lightly over the grass and other small leaves and shoots, 
so these Spider Crabs are able to climb and crawl over weeds so fine that when they are taken from 
the water they collapse into a shapeless mass. These Spider Crabs are more or less coloured to 
Photo by] "3 oe aaa CB. Step. 
THE YELLOW CRAB. 
A heavily built Crab found among stones on rocky shores and easily mistaken for a stone when at rest with 
its limbs contracted. 
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