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 1 5 |        connected with a point on the ground, for the feet appear to
 2 5 |              got their name from the ground under our feet.~Some animals,
 3 7 |        curves (undulations) upon the ground. And this is evidence that
 4 7 |        precisely as they move on the ground). Others have two fins only,
 5 9 | perpendicular at right angles to the ground.~When then one leg is advanced
 6 9 |            is at right angles to the ground and the other is advanced,
 7 9 |          either they undulate on the ground, like snakes, or up and
 8 12|           them a little way from the ground, because the whole thigh
 9 15|          whole body sprawls over the ground, and bend them obliquely.
10 16|           possibly be high above the ground.~But crabs are in nature
11 16|              they always keep on the ground. However, the flexion of
12 17|             they live in fact on the ground. Moreover, their shape is