They are not, therefore, like the wings of birds, modified from some pre-existing structures (the fore-limbs) common to their phylum; they are new and peculiar structures.
Thus the postcaval vein of the higher vertebrata is partly a new structure altogether, and is partly formed out of the pre-existing posterior cardinals.
pre-existing הגייה עם משמעויות, מילים נרדפות, הפכים, תרגומים, משפטים ועוד