The members of the American Association marched in procession to the Tent, from their place of meeting in the State Capitol. On the stage were assembled many distinguished gentlemen, and in the audience were hundreds of ladies. GOV. CLARK and Ex-Governors HUNT and SEYMOUR, of New York, Sir WM. LOGAN, of Canada, Hon. GEORGE BANCROFT, and others as well known as these, were among the number present. The tent was profusely decorated. Small banners in tri-color were distributed over the entire area covered by the stage, and adorned the wings. The following inscriptions were placed over the front of the rostrum,--that in honor of "_The Press_" occupying a central position: GEOLOGY. THE PRESS. METEOROLOGY. MINERALOGY. METALLURGY. ETHNOLOGY. ASTRONOMY. The following were arranged in various positions on the right and left: CHEMISTRY. TELEGRAPH. PHYSIOLOGY. LETTERS. CONCHOLOGY. HYDROLOGY. PALÆONTOLOGY. ZOOLOGY. MICROSCOPY. ICHTHYOLOGY. ART. MANUFACTURES. STEAM. AGRICULTURE. COMMERCE. PHYSICS. SCIENCE. ANATOMY. NAVIGATION. BOTANY. The proceedings of the day were opened with prayer by Rev. GEO. W. BETHUNE, D.D., of Brooklyn. Hon. GARRIT Y. LANSING, of Albany, then introduced Professor LOUIS AGASSIZ, of Cambridge, Mass., who was the first of the "seven men of science" to entertain his audience, always with the aid of the inevitable black-board, without which the excellent Professor would be as much at a loss as a chemist without a laboratory. Professor AGASSIZ spoke for an hour, giving his views of a new theory of animal development. He began by saying:--