I do not live the less happily on account of my anxieties, but I am sometimes obliged to work more than I well can, or ought in reason to do. . .The second number of my "Fossil Fishes" contains the beginning of the anatomy of the fishes, but only such portions as are to be found in the fossil state. I have begun with the scales; later, I treat of the bones and the teeth. Then comes the continuation of the description of the Ganoids and the Scomberoids, and an additional sheet contains a sketch of my ichthyological classification. The plates are even more successful than those of the first number. If all goes well the third number will appear next July. I long to visit your rich collections; I hope that whenever it becomes possible for me to do so, I shall have the good fortune to find you in London. . . I have thought a letter addressed to the President of the Society in particular, and to the members in general, would be fitting. Will you have the kindness to deliver it for me to Mr. Murchison? The first number of the "Fossil Fishes" had already appeared, and had been greeted with enthusiasm by scientific men. Elie de Beaumont writes Agassiz in June, 1834: "I have read with great pleasure your first number; it promises us a work as important for science as it is remarkable in execution. Do not let yourself be discouraged by obstacles of any kind; they will give way before the concert of approbation which so excellent a work will awaken. I shall always be glad to aid in overcoming any one of them." Perhaps it is as well to give here a slight sketch of this work, the execution of which was carried on during the next ten years (1833-1843). The inscription tells, in few words, the author's reverence for Humboldt and his personal gratitude to him. "These pages owe to you their existence; accept their dedication." The title gives in a broad outline the comprehensive purpose of the work: "Researches on the Fossil Fishes: comprising an Introduction to the Study of these Animals; the Comparative Anatomy of Organic Systems which may contribute to facilitate the Determination of Fossil Species; a New Classification of Fishes expressing their Relations to the Series of Formations; the Explanation of the Laws of their Succession and Development during all the Changes of the Terrestrial Globe, accompanied by General Geological Considerations; finally, the Description of about a thousand Species which no longer exist, and whose Characters have been restored from Remains contained in the Strata of the Earth."