Francis, a celebrated natural historian, was the only son of Sir Francis Willoughby, and was born in 1635. He was fond of study from his childhood, and held idleness in abhorrence; being so great an economist with regard to his time, as not willingly to lose or misapply the least part of it; by which means he attained great skill in all branches of learning, and particularly in the mathematics. But to the history of animals, which was in a great measure neglected by his countrymen, he particularly applied himself; and for this purpose carefully read over what had been written on that subject by others. He prosecuted his studies in Trinity College, Cambridge, where he took the degree of A.B. in 1656, and of A.M. in 1659. In the following year we find him residing at Oxford for the benefit of the public library. He then travelled in search of natural knowledge, several times over his native country, and afterwards into France, Spain, Italy, Germany, and the Low Countries, attended by his ingenious friend John Ray. It is remarkable that, notwithstanding the advantages of birth, fortune, and parts, he was as humble as any man of the meanest fortune; was sober, temperate, and chaste; scrupulously just; so true to his word and promise that a man might venture his estate and life upon it; so faithful and constant to his friend as never to desert him when fortune frowned upon him; and remarkably pious, patient, and submissive to the divine will. This is the character given of him by Mr Ray, whose veracity none will doubt. This ingenious and learned gentleman died on the 3d of July 1672, at the age of thirty-seven, having impaired his health by his application. He wrote,

1. Ornithologiae libri tres, 1676, fol. It was afterwards translated into English, with an appendix, by Mr Ray.

2. Historiae Piscium libri quattuor, 1686, fol.

3. Letters of Francis Willughby, Esq., added to Philosophical Letters between the learned Mr Ray and several of his correspondents, and published by Dr Derham.

4. Several ingenious papers in the Philosophical Transactions.