I wish you would ask Trudeau whether _he_ recollects the specimen of an Eagle send by Townsend in his first collection, numbering 54 and which the latter has lost, though he considered it as a new species. It was procured in California. Townsend speaks sorrowfully of the loss of this specimen. It never came under my eye, did it come under yours? Ask Trudeau whether he ever saw my Hirundo Serripennis in America. Bachman wrote to me that Trudeau thought he had in the skins of Frederick Ward. I think Trudeau will be pleased with the anatomy of our birds, as it opens misteries hitherto unknown in connection with the relative affinities of some species toward others and assists in the formation of groups &c., in what some day or other, will be called a _Natural arrangement_! I wish I could have spent a few weeks in Paris with you and Trudeau, as I readily imagine that some new species of North American birds, may yet be found there unknown to the World of Science. I have written to Mr. Chevalier and to Townsend, but will not, I dare say, hear anything more of the former until through Victor, who intends to see him very shortly after his arrival in America. My Dear Wife is much better than when you saw her, and I hope that when once again she has been safely landed on our shores and enjoyed the warmth of our own Summers, her health will be quite restored. The _Little_ Lucy has grown as fat as butter, and the rest of us are well. We all unite in kindest best wishes to you and to Trudeau, and I remain as ever, my Dear Friend, Yours, JOHN J. AUDUBON. 6 Alva Street. In May, 1839, Audubon's fifth and last volume of the _Ornithological Biography_, consisting of 704 pages, was issued. It was followed almost immediately by _A Synopsis of the Birds of North America_, in which the efficient aid of MacGillivray was again enlisted. On May 4 Audubon wrote to Havell that this work was in press and would be ready in about a month's time; again, on the 30th of June he announced that it was finished and in the hands of the binder. With this methodical catalogue of the birds of North America then known and described, to the number of 491, fifty-two of which were new, Audubon's life and labors in England were brought to a close. The introduction to the last volume of his "Biographies" begins as follows: