Prof. Agassiz taught at Penikese partly by lectures, and these lectures, as was his custom, were always extemporaneous. No one who ever heard him need be told that beyond all comparison he was the model scientific talker of the age. Even those who have but read his lectures know what a charm lingers in the sentences which have been transferred to paper. But one must have heard him to realize the secret of his greatest power. The printed lectures carry the brilliant thoughts, the luminous and interesting facts, the flow of apt illustration; but the glow and fervor of his own profound interest in the matter of his speech, “raying out in a countenance that seemed to beam from interior light, and pervade the tones of his sympathetic and singularly expressive voice,” the “palpitating life” of his rapidly-uttered words, and back of all his intense personal magnetism, diffusing itself through the hearts of his charmed audience,—these are things that can not be transferred to paper. Writers in attempting to describe the manner of his eloquence have seemed to exhaust the vocabulary of eulogy. At Penikese he probably excelled himself. He complimented his school by seeming to believe that he was in the midst of friends, who fully appreciated him, and who were in full sympathy with him. In 1864 it was the good fortune of the writer of this paper to hear him deliver a course of six lectures on the glaciers, before the Lowell Institute, in Boston. They were charming, popular, grand; but at Penikese, on the same subject, he seemed like a different man. All through his summer life there flowed a current of quiet but profound happiness, that lightened his step, glowed in his conversation, shone in his countenance, and gave animation and radiance to his lectures, in a manner he perhaps never before so fully exhibited. This thought was common among the students there assembled. He gave lectures almost every day, embracing full and exhaustive courses upon the glaciers, upon embryology, upon classification, upon methods of instruction, upon systematic zoölogy, upon scientific books and authors. There were also the spontaneous lectures, called out by some casual remark, the exhibition of some new and interesting specimen, or by the prominent presence of some object of natural history, which we might not think of studying at the time. For example, we were regaled one morning with some fish for breakfast. Prof. Agassiz, entering after the rest were seated, noticed the fish. Going immediately to the black-board, which at that time was near and in full view; he said: “Ladies and gentlemen: You are this morning feasting upon a very delicious fish, called the scop. Its scientific name I will write upon the board. It is Pagrus Argyrops—one of the sparoids. This species is not found north of Cape Cod, or at least, very rarely found. Its range is from Cape Cod west and southward. It is not found in the southern waters, only