that, in the strain and shock to which the ship had been submitted, the rudder was broken. In view of this new disaster, the passengers for Pará gave up all hope of meeting the steamer at Manaos, and the rest resigned themselves to waiting with such philosophy as they could muster. The whole of that day and the following night were spent in rigging up a new rudder, and it was not until eight o’clock on Sunday morning that we were once more on our way, arriving at Teffé at eleven o’clock. ----- Footnote 59: As will be seen hereafter, want of time and the engrossing character of his work in the Amazons, compelled Mr. Agassiz to renounce the journey into Peru, as also the ascent of the river Madeira. Footnote 60: _To His Excellency M. Couto de Magalhaēs, President of Pará._ MY DEAR SIR:—I thank you sincerely for the kind letter you were so good as to write me last week, and I hasten to inform you of the extraordinary success which continues to crown our efforts. It is certain from this time forth, that the number of fishes inhabiting the Amazons greatly exceeds all that has hitherto been imagined, and that their distribution is very limited on the whole, though a small number of species have followed us since we left Pará and others have a range more or less extensive. You remember, perhaps, that, when alluding to my hopes, I told you one day that I believed in the possibility of finding from two hundred and fifty to three hundred species of fish in the whole basin of the Amazons; even now, having passed over less than one third of the main stream, and only diverged here and there to some points beyond its shores, I have already obtained more than three hundred. It is incredible, above all, if one considers that the total number known to naturalists does not reach one third of what I have already collected. This result scarcely allows one to foresee the discoveries to be made whenever the affluents of the great river are explored with the same care. An exploration of the Araguay for its whole course, in order to teach us how many different combinations of distinct species occur in succession, from its sources to its junction with the Tocantins and lower down till it meets the Amazons, would be an enterprise worthy of you. You have already a sort of scientific property in this river, to which you would add new rights in furnishing science with this information.