The Cambridge Philosophical Society has been employed from the period of its first establishment in 1819, in gradually forming a Museum of Natural History. With a view to this end, it has from time to time effected several purchases, as well as received the contributions of various donors. The Museum however is not large; partly owing to the limited funds which can be appropriated to its support, and partly to the necessarily restricted space allotted for its reception in the Society's house. It is principally, though not exclusively, devoted to the illustration of the British Fauna. The foundation of the Museum may be attributed to Professor Henslow, who presented to the Society at its first institution his entire collection of British Insects and Shells, arranged respectively in two cabinets. Several smaller donations quickly followed, leading the Society to take an increased interest in this part of its establishment. In 1828, a spirited subscription was commenced amongst its members to assist in purchasing a most valuable collection of British Birds, for obtaining which an opportunity then offered itself. This collection had belonged formerly to Mr. John Morgan of London. It was extremely rich, especially in the rarer species. Many additions however have been since made to it; and the whole forms now a range of thirty large cases, which are placed round the principal room in the Museum.