He next proceeded to show that organized beings were organized with reference to a plan, which the relations between different animals, and between different plants, and between animals and plants, everywhere exhibit;--drew sections of the body of a fish, and of the bird, and of man, and pointed out that in each there was the same central back-bone, the cavity above and the ribbed cavity below the flesh on each side, and the skin over all--showing that the maker of each possessed the same thought--followed the same plan of structure. And upon that plan He had made all the kinds of quadrupeds, 2,000 in number, all the kinds of birds, 7,000 in number, all of the reptiles, 2,000 to 3,000 in number, all the fish, 10,000 to 12,000 in number. All their forms may be derived as different expressions of the same formula. There are only four of these great types; or, said he, may I not call them the four tunes on which Divinity has played the harmonies that have peopled, in living and beautiful reality, the whole world? PROFESSOR HITCHCOCK ON REMINISCENCES. ERASTUS C. BENEDICT, Esq. of New York, introduced Prof. HITCHCOCK, of Amherst, as a gentleman whose name was very familiar, who had laid aside, voluntarily, the charge of one of the largest colleges in New England, but who could never lay aside the honors he had earned in the literature and science of geology. After a few introductory observations, Prof. HITCHCOCK said:--