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Show 1899.] THE MYOLOGY OF THE EDENTATA. 331 scapular head is noted as rising from just below the glenoid cavity The fibres of the inner head have the same pulley-like arrangement as in Myrmecophaga, as shown by Cuvier and Laurillard's figure (16), and by Bapp's description of them as forming a humeral head for the flexor profundus digitorum (III.). Of the five specimens of Cyclothurus of which Ave have records, three had only one scapular head (17, 18, 21), whilst in two (19, 20) this was double. In one of the first-named group (21) a continuation of the muscle into the forearm, as in Tamandua and Myrmecophaga, Avas present. In all the Myrmecophagidce the anconeus is large, and especially so in Cyclothurus. The Dasypodidce resemble the last family iu having, as a rule, two scapular heads, which may be called anterior and posterior. The anterior rises from the axillary border below the glenoid cavity, and the posterior from the dorsum scapulas in the region of the lower spine. This applies to Dasypus (22), Tatusia (25), and Chlamydophorus (27,28). In Galton's specimen of Dasypus (23) the long head Avas apparently single, while in one specimen of Chlamydophorus (27) there was a third scapular head from the inferior margin of the bone. In the Manidce the scapular head is also usually double, this condition having been noticed in three cases (29, 31, 34) ; in two cases (32, 33) no division was seen. In Oryeteropus multiple scapular heads seem to be the rule. In 36 there are three, viz. (a) glenoid, (b) from the posterior costa, (c) from the angle, passing to the triceps and the latissimo-olecranalis. In (35) only two were noticed, but one of them seems as if it would be more properly described as a scapular origin of the latissimo-olecranalis, and the same thing seems to have been present in (31). Macalister (VII.) notices that in a specimen which he dissected the lower fibres of the inner head play round the internal condyle and join the flexor profundus as in the Myrmecophagidce. The anconeus presents no special features of interest in the Manidce and Orycteropodidce. In conclusion, we may point out that all the Edentata, with the exception of the Bradypodidce, are remarkable for the great development and complexity of the extensor cubiti and for the presence of additional scapular origins. Epitrochleo-olecranalis.-We can confirm Galton and Gruber's observations as to the constancy and remarkable development of this muscle throughout the Edentata. Pronator radii teres rises from the internal condyle and seems to be always inserted into the lower third or half of the radius. This arrangement we find to be so constant that it may be fairly looked upon as an Edentate characteristic. Flexor carpi radialis.-Unlike most mammals the Edentates shoAV some variability in the insertion of this muscle, though its origin from the internal condyle is constant enough. In the Bradypodidce it never seems to obtain its normal insertion into the second metacarpal bone. In four specimens of Bradypus (2, 3, 5, 6) it was inserted into the rudimentary trapezium. Mackintosh (5) found a small muscle, which he calls flexor carpi radialis profundus, rising from the ulna and running down to the deep |
