One of the most charming of Leonardo's drawings, this sheet ranges from acutely observed studies of domestic cats, through seven drawings of a prowling lioness, to a highly stylised coiling dragon. The incomplete note at the bottom of the sheet reads: 'Of flexion and extension. This animal species, of which the lion is the prince because of its spinal column which is flexible'. Late in life Leonardo proposed a treatise on the movement of animals. It is clear, therefore, that his interest here was the variety of positions and movements attainable by the cat family. The dragon was added as a still more extreme case, limited only by the artist's imagination rather than by real anatomy.