. Bulletin of the British Ornithologists' Club. a very shallow notch in the proximal pro- file; and (9) in caudal view the ventral margin from the ventral tubercle around the bicipital crest is evenly convex. The humeri of Anhimidae and Anseranatidae differ markedly as follows: capital shaft ridge strongly directed towards the head; dorsal pneumotricipital fossa obsolete; lamina around the disto- ventral margin of the ventral pneumatic fossa (character 2) larger, partially occlud- ing the fossa; ventral pneumatic fossa comparatively smaller; distal extent of entepicondyle less than dorsal cond
. Bulletin of the British Ornithologists' Club. a very shallow notch in the proximal pro- file; and (9) in caudal view the ventral margin from the ventral tubercle around the bicipital crest is evenly convex. The humeri of Anhimidae and Anseranatidae differ markedly as follows: capital shaft ridge strongly directed towards the head; dorsal pneumotricipital fossa obsolete; lamina around the disto- ventral margin of the ventral pneumatic fossa (character 2) larger, partially occlud- ing the fossa; ventral pneumatic fossa comparatively smaller; distal extent of entepicondyle less than dorsal condyle; distinct dorsal supracondylar prominence; and external tricipital groove lacking. The humeri of Dendrocygna differ markedly in having a prominent capital shaft ridge directed towards the head and a promi- nent dorsal supracondylar prominence. The pneumatic ventral pneumotricipital fossa distinguishes A. scaldii from the non- pneumatic state in Thalassornis, Oxyura, Biziura, Malacorhynchus, some Mergini Somateria, Melanitta, Clangula, Bucephala, and some Aythyini. The Tadornini, although having similar proportions, differ in character 2, with the distoventral lamina merging with the floor in the ventral half of the ventral pneumatic fossa. Tadornini further differ in the configuration of the ventral margin of the bicipital crest. In A. scaldii this is evenly convex and extends ventrally of the ventral tubercle, as in Anserini, but in Tadornini {Tadorna, Alopochen, Cyanochen) the ventral tubercle is more prominent ventrally, so that when the humerus is viewed in a proximo- caudal direction, the ventral margin either forms a straight edge parallel to the capital shaft ridge, or it has a shallow notch distal of the ventral tubercle. Presence of a capi- tal shaft ridge, elevated dorsal tubercle, and the dorsally concave deltoid crest, as in Anserini and Tadornini, are all pie-. Figure 1. Humeri in caudal view. A. Anser scaldii IRSNB Av69; B. Branta bernida USNM 492443; C.
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