Thus constituted, the deep flexor goes towards the phalanges, where it terminates as the deep flexor of the digits of the fore-limbs (see p. 197). In animals possessed of a canon it contributes to form the _tendon_ (Fig. 85, 16; Fig. 86, 14, 14; Fig. 88, 19, 19). Muscles of the Foot We must remember that on the dorsal surface of the foot in man we find but a single muscle--the dorsalis pedis. The remaining subcutaneous structures of this region consist of the tendons of the anterior muscles of the leg which occupy this dorsal aspect. =Dorsalis Pedis= (Fig. 84, 19).--Also called the extensor brevis digitorum, the dorsalis pedis muscle is found in all domestic quadrupeds; but its development is so much the less as the number of digits is more reduced. In the dog and the cat it arises from the calcaneum, and is inserted into the three internal toes (the first toe excepted) by uniting with the corresponding tendons of the common extensor. In the pig its disposition is analogous. As for the dorsalis pedis of the ox and the horse, it is extremely rudimentary, and occupies the superior part of the canon. It is a small, fleshy body, situated on the anterior surface of the metatarsus, which arises from the calcaneum, whence it passes to unite at its inferior extremity with the tendon of the extensor of the phalanges. As regards the muscles of the sole of the foot, we think it unnecessary to occupy ourselves at any length with them because of their slight importance with regard to external form. We will only recall that in the median portion of this plantar surface we find in man the short flexor of the toes, which in quadrupeds arises higher up, from the posterior surface of the femur; that it belongs to the muscles of the leg; and that it forms the superficial flexor of the toes, which we have already studied. We may further add that the suspensory ligament of the fetlock in ruminants and solipeds represents, as in the fore-limbs, the interosseous muscles. MUSCLES OF THE HEAD We will divide these muscles into two categories: masticatory and cutaneous. Masticatory Muscles The muscles of this group which specially interest us are the masseter and the temporal. As regards the pterygoids, since they are situated within the borders of the inferior maxillary bone, and consequently do not reach the surface, we shall not require to occupy ourselves with them here. =Masseter= (Fig. 89, 2; Fig. 90, 1; Figs. 91, 92).--For those who have studied the masseter of man, it is not difficult to recognise that of quadrupeds. Nevertheless, the particular aspect which it presents in different species gives to its study a certain interest. Arising from the zygomatic arch, and passing downwards and backwards, it is inserted into the external surface of the ramus of the mandible and into its angle.