As far as we could, consistently with the plan laid down in the following work, we have consulted, and we trust with some advantage, the works of Willoughby, Ray, and other naturalists. In the arrangement of the various classes, as well as in the descriptive part, we have taken as guides our intelligent and indefatigable countrymen, Pennant and Lathamf'f to whose elegant and useful labours the world is indebted for a fund of the most rational entertainment, and who will be remembered by every lover of Nature as long as her works have power to charm. The communications with which we have been favoured by those gentlemen who wefe so good as to notice our growing work, have been generally acknowledged, each in its proper place; it remains only that we be permitted to insert this testimony of our grateful sense of them.