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Show 276 MESSRS. B. C. A. WINDLE AND F. G. PARSONS ON [Nov. 3, which by cutting the rectus and turning its origin up, evidence of the two heads could not be found. Lesbres (V.) says that in the Pig, Sheep, and Goat the reflected head is absent; we have, however, paid special attention to the point in the Pig (11, 14) and Sheep (46, 47), and are convinced that both heads are really there. With regard to the crureus in Ungulates, we have often noticed that it is more distinct than in many other orders of mammals, and it rises from all three surfaces of the femur. Sometimes, as in the Ox (40) and Sheep (41), it is divided more or less completely into an inner and an outer portion. The vastus externus is usually larger than the internus, but in the Tapir (61, 62) both Murie and ourselves were struck by the enormous size of the vastus internus. The nerve-supply of the quadriceps is always the anterior crural. Anterior Tibial Region. Tibialis anticus.-This muscle usually has a femoral origin from the front of the external condyle, rising with the extensor longus digitorum, as well as a tibial origin from a small part of the upper and front portion of the tibia. In the Hippopotamus (3) the two parts are quite separate, the tibial portion being inserted into the base of the second (index) metatarsal, while the condylar part forms an arch in front of the ankle which binds down the extensor tendons, the two horns of the arch being attached to the bases of the index and minimus metatarsals. In the Suidaa (4, 5, 11, 14) the two parts are also distinct, but the fibrous arch is not present, and they are both inserted into the index metatarsal and middle cuneiform bones. In all the other Artiodactyla, viz. Chevrotain (22, also the " Napu Deer " described by Haughton XV., which is the Javan Chevrotain), Virginian Deer, Nylghau, Elk (30), Brocket Deer (29), Sheep (47, 48), Ox (35, 40), Goat (50, 52), and Antelope (54, 55), the arrangement is practically identical with that of the Duiker-bok (54), the variations being very slight. In this animal (54) the femoral head is the larger, and opposite the ankle is pierced by the tibial tendon, it is then inserted into the inner side of the dorsum of the base of the large metatarsal bone, which is common to the medius and annularis digits. The tibial tendon, which pierces the one just described, runs to the ventral part of the inner side of the base of the same metatarsal bone. In the Perissodactyla the same femoral and tibial origins are found in the Tapiridae (61, 62) and Equidae (63, 64, 65), and the same perforation occurs in the Horse, though we did not notice it in the Tapir (61). As to the Rhinoceros we have not sufficient data to form an opinion. In the Subungulata the femoral origin is absent; this is the case in both the Hyrax (74, 75) and the Elephant (80, 81, 84, 85). In the Hyrax its insertion is into the second metatarsal, while in the Elephant it is usually inserted into the first as well. It is always supplied by the anterior tibial nerve. |