Abstract
Four main positions of circumscribed stresses in carnivores are distinguished as exemplified by the conditions in (i) Canidae, (ii) Felidae, (iii) Machairondontinae and Odobenidae, and (iv) Otaridae and Phocidae. The functional transformations in the last two divisions are discussed with reference to the Canidae and Felidae. The changes in Phocidae and Otaridae are caused by the vanishing of the maxillary node. In Smilodon, the moments of the masseter and temporal muscle and the way in which the muscular torque is formed in the cat and Smilodon, are discussed. The extinction of Smilodon is explained in a mechanical way. In connection with it further relations of force are analysed with special reference to the torque and its moments. The skull of Mustelidae is briefly discussed as an example of transposition caused by a different type of locomotion.