Sentence:  "I wish we were back in Tenth Street. But so many children came...and the Tenth Street house wasn't half big enough; and a dreadful speculative builder built this house and persuaded Austin to buy it. Oh, dear, and here we are among the rich and great; and the steel kings and copper kings and oil kings and their <WSD>heirs</WSD> and dauphins.nb..." 
Meaning of the word marked with <WSD> tags:  A successor in a role, representing continuity with the predecessor.