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Show 1879.] ANATOMY OF HYiENA CROCUTA. 103 is inserted into the whole length of the linea aspera, as well as the internal of its lower bifurcations. Rectus femoris is tolerably well developed. It originates partly from the anterior (inferior) spinous process of the ilium, and also by a well-marked reflected tendon from the dorsum acetabuli. In the Civet the two heads exist as usual, whilst in H. striata Meckel fonnd that the two heads of origin were not distinct. The muscle terminates in the usual manner. The vasti muscles, as in H. striata, are hardly separable. They form a large muscular mass which arises from the upper half of the shaft of the femur, and, with the rectus femoris and the straight. fibres of the sartorius, are inserted into the anterior tubercle of the tibia. Crureus is absent or is not to be differentiated from the vasti. In the Civet there is a much more strongly marked distinction between these deeper heads of the quadriceps extensor. Gastrocnemius, well developed, arises by two heads as usual; its insertion below is into the os calcis. The soleus is wanting. In this respect H. crocuta agrees with H. striata and with the Dog and Cat1, but contrasts strongly with the Civet, in which the soleus exists as a separate muscle throughout. It is also present in the Bear. Plantaris.-This arises along with, but internal to the external head of origin of the gastrocnemius. Its tendon joins that of the latter muscle low down, close to the os calcis, and is inserted with it. The plantaris-tendon is not continued into the sole, either as the plantar fascia or as the flexor brevis digitorum. Iii the Civet the plantaris is comparatively large, and its tendon does not end at the os calcis, but, expanding somewhat, runs over the tuberosity of that bone to become continuous with the flexor brevis digitorum. Meckel notes a similar prolongation of the muscle into the foot in H. striata. Popliteus is from the external femoral condyle. Its insertion is into the posterior surface of the tibia above the oblique line, and further, extending halfway down the shaft. It is similarly arranged in H. striata and the Civet. The tibialis posticus, as usual in Carnivores, is small but normal. Very thin and slender in H. crocuta, it arises below the popliteus from the middle third of the postero-internal border of the tibia. Its tendon is inserted into the scaphoid and entocuneiform bones. The long flexor of the toes (perforans), representing the conjoined flexor longus hallucis and flexor longus digitorum of human anatomy, arises by two heads, of which the internal (flexor longus digitorum) is small and springs from the head of the fibula and intermuscular septa separating it from neighbouring muscles. The external head (flexor longus hallucis) is much larger; it arises from the superior extremity and upper half of the shaft of fibula, from a corresponding extent of tibia, and from the interosseous membrane. Each of these heads terminates on a distinct tendon, which, passing through a separate sheath in the annular ligament, unite in the sole of the foot 1 Chauveau's ' Comparative Anatomy.' translated by Fleming, p. 309. |