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Their circulation cannot, therefore, be as active as among the higher animals ; and their blood is cold like that of Reptiles. Their skin is covered only with scales, which, in some instances, are scarcely discoverable, so that the skin appears quite bare ; they have no mammary glands like the Mammalia, and they are reproduced by means of eggs ; lastly, their members have the form of fins. Now it is impossible to convert such proposition make it in any sense true. Soft-shell crab does not in any genetic sense become what is simpler than itself. We cannot read forward from to by any logical process nor can we read back from to logically for the con- nection is one of becoming genesis does not work backward. prev next |