We sometimes find in man, but abnormally, an arrangement which partly recalls that which we have just indicated. It consists in a duplication of the tendon of the short peroneal, one of the branches of which goes to the fifth metatarsal, and the other to the fifth toe; it is sometimes a single fasciculus which goes to the phalanges of this latter. We have met with examples of these anomalies.[31] In the pig, the short peroneal is situated on the same plane as the long. It consists of two clearly distinct fasciculi, which arise from the fibula. The tendon of the anterior fasciculus proceeds to the great external toe--that is to say, the fourth, of which it is the proper extensor. The posterior fasciculus terminates on the small external toe, the fifth, of which it is in like manner the extensor. [31] Édouard Cuyer, 'Anomalies, Osseous and Muscular' (_Bulletins de la Société d'Anthropologie_, Paris, 1891). In the ox, the fleshy fibres of the short peroneal arise from a fibrous band which replaces the fibula, and from the external tuberosity of the tibia. Situated behind the long peroneal and on the same plane, it terminates in a tendon which appears at the level of the inferior part of the leg; it passes in front of the canon, and is inserted into the external toe, of which it is the proper extensor. In the horse, it is the sole representative of the peroneal muscles, and veterinary anatomists have given it the name of _the lateral extensor of the phalanges_. Its fleshy body arises above from the external lateral ligament of the knee-joint, and from the whole length of the fibula. In the middle third of the leg it is narrowed; lower down it is replaced by a tendon. This is lodged in a groove hollowed on the external surface of the inferior extremity of the tibia; then after passing along the external surface of the tarsus, it is directed forward, and proceeds to blend towards the middle of the canon-bone with the tendon of the long extensor of the toes, or anterior extensor of the phalanges, of which it shares the insertions. It extends the phalanges into which it is inserted. It also flexes the foot. Muscles of the Posterior Region It will not be unprofitable to recall to mind that, in man, the muscles of this region are arranged in two layers: a superficial layer consisting of the gastrocnemius and soleus, to which is added a muscle of little importance, the plantaris, and a deep layer formed by four muscles--the popliteus, flexor longus digitorum, tibialis posticus, and flexor longus pollicis. The gastrocnemius and soleus, independent in their upper portion, unite below in a common tendon; they thus form also a triceps muscle, which we designate under the name of the triceps of the leg, or triceps suralis, because it forms the elevation of the calf of the leg (from _sura_, calf).