This is a page from a small notebook otherwise devoted to human anatomy. The drawings show the two-horned uterus of a cow, with a foetal calf in the upper ‘horn’ (visible in the lower drawing, lying on its back with its legs upwards). Leonardo wrote in the accompanying notes that, on the birth of the calf, the placental cotyledons united (in the manner of the honeycomb sketched at upper left) to be delivered as a single afterbirth.