. Bulletin. Natural history. fig. 27. A, proximal; B, distal views of humerus illustrated in Fig. 26. XI. Abbreviations as in Fig. 26. was probably occupied by supracoracoid insertion. The remainder of the margin is beveled on both sides, creating a sharp edge bowed slightly ventrally (Fig. 26B,C). The flange abruptly terminates at a small marginal tuberosity equidistant from the proximal and distal ends of the humerus; from this tuberosity a low ridge runs postero- distally to bridge the entepicondylar foramen. Deltoid musculature may be reconstructed as inserting on the beveled anterolateral
. Bulletin. Natural history. fig. 27. A, proximal; B, distal views of humerus illustrated in Fig. 26. XI. Abbreviations as in Fig. 26. was probably occupied by supracoracoid insertion. The remainder of the margin is beveled on both sides, creating a sharp edge bowed slightly ventrally (Fig. 26B,C). The flange abruptly terminates at a small marginal tuberosity equidistant from the proximal and distal ends of the humerus; from this tuberosity a low ridge runs postero- distally to bridge the entepicondylar foramen. Deltoid musculature may be reconstructed as inserting on the beveled anterolateral margin and terminal tuberosity of the deltopectoral The entire posteromedial margin of the crest margin bears a pattern of striations and rugosity w-hich may indi- cate die M. pectoralis insertion. The entire anterolateral surface of the deltopectoral crest is occupied by a shallow but broad fossa (/ br, Figs. 26C, 28E) probably repre- senting the origin of the M. brachialis. A prominent ridge runs anteroproximally be- tween the fossa and the humeral head (r tm, Fig. 26A) and may possibly indicate the insertion for a teres minor. From the ridge just described another ridge runs obliquely across the dorsal surface of the humeral shaft {rid, Fig. 26A). It is low and irregular and conceivably repre- sents the insertion for the M. latissimus dorsi. A groove, more distally placed, parallels the shaft along its posteromedial aspect (gr, Fig. 26A). In one excellently preserved specimen (BPI 1675) it is clear that the irregular ridge and groove are confluent, and therefore the groove may represent the initial differentiation of the insertion of the M. teres major from that of the M. latissimus dorsi. It is equally possible that one or both of these features represents the origin of one of the humeral triceps heads. Oval entepi- and ectepicondylar foramina pass distoventrally through the bone adjacent to the epicondyles and each is obliquely inclined away from the shaft. Broom
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