Paragraph

 1 2 |         accustomed constantly to use for our scientific investigation
 2 3 |        change of position by the use of at least two parts of
 3 5 | quadruped, polypod, limbless). I use the term foot for a member
 4 6 |    animals which progress by the use of distinct members have
 5 7 |          put the sea to the same use as snakes do both land and
 6 9 |      have said before. Flat fish use two fins, and the flat of
 7 10|          are ill-adapted for the use in question, for example
 8 10|        have a tail that is of no use; for instance the purple
 9 10|       substitute for a tail, and use their legs instead of a
10 10|           and so the flight they use is like a cargo boat attempting
11 12|         changing position by the use of limbs, must have one
12 16|           and the fact that they use them not for swimming but