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Show 98 MESSRS. WATSON AND YOUNG ON THE [Jan. 14, The coraco-brachialis is a c. brevis (Wood). It springs from the upper border of glenoid cavity, and passes to the shaft of the humerus just above the insertion of the latissimus. Such, according to Wood1, is also the arrangement in the Dog and Cat; and so have we found it in the Civet. In other of the Carnivora, e. g. Bears, the coraco-brachialis exists as a double muscle, corresponding to the long and short varieties of Wood. The triceps possesses four distinct heads. Of these the scapular, very large, springs from nearly the whole length of the axillary costa of scapula. The second and third arise from the upper third of the humeral shaft, and are separated by the origin of brachialis anticus. The fourth head is a small muscular bundle from the olecranon-fossa and adjoining part of the shaft of humerus. These heads have a common insertion into the olecranon process of ulna. In the Civet the muscle is similarly constituted; the long head, however, is more limited at its scapular attachment. Supinator longus is absent; a tendinous vestige exists and apparently represents it. According to Meckel it is also wanting in H. striata ; whilst Douglas records its absence in the Dog. In the Civet, however, it exists, comparatively small and feeble, but quite distinct. The extensores carpi radiates longior et brevior arise conjointly from the outer condyloid ridge of humerus. Fused for some distance the two muscles are inseparable; the respective fibres, however, terminate on two separate tendons, which are inserted into the metacarpals of index and middle digits. The muscular fibres at the origin are similarly interblended in the Civet and Dog, whilst in H. striata Meckel describes the muscles as distinct throughout, the tendons being united by a transverse band. Extensor communis digitorum, from the outer condyle and intermuscular fascia, terminates in the usual manner, passing to the four outer toes. There is an extensor carpi ulnaris, from the external condyle to the base of metacarpal of little digit. A small supinator brevis passes from the orbicular and external lateral ligaments to the radius anteriorly, reaching just belowtheelbow. A double extensor minimi digiti spriugs from the outer humeral condyle; its tendons pass to the two outermost digits (annularis and minimus). The same obtains in H. striata. In the Civet the muscle terminates by three tendons, which are distributed to the three outer toes ; whilst, according to Douglas, in the Dog there is but a single tendon of insertion, this being confined to the fourth digit (annularis). The extensor primi internodii is wanting or is quite inseparable from the extensor ossis metacarpi pollicis. The latter arises from the whole length of internal surface of ulna and adjoining interosseous membrane, and also slightly from the upper end of the radius. It is inserted into the base of rudimentary pollex. Such also is the arrangement in the Dog, Civet, and H. striata. An extensor indicis passes from the middle of the external border 1 Wood, " on Muscular Variations," Journal Anat. and Phys. vol. i. p. 55. |