Ambitious to have my name associated, in some respects, with one who has so long and so justly enjoyed so liberal a share of public estimation, has induced me to take this opportunity of addressing you, and of requesting you to accept of a copy of my recent work, which has for its object, a concise and s-cientific des-cription and classifycation of the mammiferous animals of N.America.—At the same time I have the pleasure of forwarding to you, a des-cription of the “Horned lizard” which you presented to the Amer. Philos. Soc. many years ago, and which has not heretofore been s-cientifically noticed, or properly arranged in the systems,— but was confounded with the “Orbicular lizards”—Allow me to add a copy of an esay on these new genera of Animals, which I have lately des-cribed—Also one of my Phrenological lectures.

For the few years I have dedicated my time to the study of Zoology and Comparative Anatomy, your name has frequently presented itself as one of the earliest and most distinguished cultivators of Nat. Science—on the continent of America.—

Although the frost of years must necessarily moderate enthusiasm, yet have we, in yourself, a consoling example, that the shackles of age can not extinguish the sacred thirst of knowledge—like the chaste and modest rays of the Setting Sun, your fame will continue to shed her beams, with a tender and kindly influence on the rising votaries of a science, the successful cultivation of which must have its share in the destinies of a nation, and even now is requisite to form the Corrinthian wreathe for the Colossean Columns of Freedom.—