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Show 1899.] THE MY0L0SY OF THE EDENPATA. 327 superficially to the others, while the spinous fibres are inserted highest and pass deep to the other two bundles. In those animals in which the clavicle is absent or rudimentary, the chwicular part of the muscle is continuous Avith the ventral fibres of the trapezius to form a cephalo-humeral. Among the Bradypodidce, Bradypus has the cephalo-humeral, acromial, aud spinous parts closely blended and inserted into the middle of the humerus (1, 3, 4). In two specimens (4, 5) a slip Avas given to the short bead of the biceps from the cephalo-humeral. In Cholcepus the insertion varied in two specimens-in one (10) the clavicular and acromial portions were both inserted into the radius, AAiiile in another (8) all three parts went to the deltoid tubercle. Among the Myrmecophagidce, Myrmecophaga (11, 12, 13) and Tamandua (14, 16) have each a cephalo-humeral aud all three parts are inserted into the middle of the humerus. In Cyclothurus (17, 18, 19, 21) the clavicular, spinous, and acromial parts are all inserted into the humerus together, the two latter being apparently closely fused. In the Dasypodidce the clavicular slip rises from the clavicle in Dasypus (22, 23), Tatusia (25, 26), and Chlamydophorus (27', 28), and is always inserted into the deltoid tubercle on the humerus. The acromial and spinous parts may or may not be separate. In the Manidce the cephalo-humeral is well marked, the spinous and acromial parts are more or less fused, and in several specimens (29, 32, 33, 34) a separate bundle Avas traced from the spine of the scapula to the triceps or supinator longus. Macalister expresses some doubt as to the nature of this slip; but we have been able to satisfy ourselves, by tracing the circumflex nerve into it, that it is a part of the deltoid. In the Orycteropodidoz the clavicular portion is inserted into the radius Avith the biceps, the other two parts passing to the deltoid ridge (35, 36, 37). Supra- and Lnfraspinati.-In all cases the supra- is considerably larger than the infraspinatus. In Dasypus (22, 23) the latter muscle rises between the two scapular spines. Teretes major et minor.-One of the great characteristics of all members of the Edentate Order, Avith the sole exception of the Myrmecophagidce, is the great development of the teres major. In many of these animals there is a considerable ridge of bone marking off the origin of the teretes from that of the infraspinatus. Of this ridge, which is called the inferior scapular spine, we have already written in connection with Dasypus. The teres minor in most of the Order has been described as present. In some cases it is described as being fused with the infraspinatus or subscapu-laris, but from our own experience of the Order Ave can quite ensily understand how* two observers, in the instances in wiiich the muscle is not Avell marked, might readily differ in their description of the same animal, so that we shall content ourselves by saying that this muscle is usually a distinct entity throughout the Edentata. Subscapular is.-In the Bradypodidce the bundle of fibres rising from the axillary border of the scapula and obtaining an insertion 22* |
