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Show 1044 MR. W. P. PYCRAFT ON T H E [Dec. 19, B. Greatest width of sternum across posterior lateral processes more than \- sometimes equal to-its whole length ; metasternum deeply notched, not projecting so far back as ends of posterior lateral processes; coracoid groove very deep ; no spina externa or interna; no precoracoid ; posterior lateral processes'of coracoid short and blunt; scapula with long acromion. PoDICIPEDIDcE. D. PELVIC GIRDLE. Greatly elongated and compressed laterally behind the acetabulum ; closely resembles that of the Cretaceous Hesperornis, and differs entirely from that of any other living Carinate bird, the postacetabular ilium being represented by a nearly vertical plate of bone; synsacrum almost styliform; pleurostea caudad of acetabulum wanting ; parapophyses vestigial. A. Free end of pubes spatulate COLYMBIDCE. B. Free end of pubes not spatulate PODICIPEDIP.E. E. PECTORAL LIMB. The bones of the wing are relatively long; the humerus has a moderately well-developed delto-pectoral crest, the coraco-humeral groove takes the form of a deep pit; there is a shallow fossa for the brachialis internus; the fossa subtrochantericus is blind. The forearm is nearly or quite as long as the arm. Mc. III. is long, slender, and runs parallel with Mc. II. A. Carpo-metacarpus much elongated ; Mc. I. very long, ^ as long as Mc. II.; manus as long as forearm COLYMBI DM. B. Carpo-metacarpus not greatly elongated ; Mc. I. very short; manus shorter than forearm PODICIPEDIDCE. E. PELVIC LIMB. (Pigs. 1-3, pp. 1038-9.) Femur very short; tibio-tarsus with an enormous cnemial crest; tarso-metatarsus laterally compressed; outer toe longest; ungual phalanges much flattened. A. Cnemial crest as long as or longer than femur ; fibula extending downwards to the tarsus, or very nearly so ; the ecto-trochlear foramen of tarso-metatarsus tubular; hypotarsus simple COLYMEIDCE. B. Cnemial crest shorter than femur; fibula terminating near the lower i of the leg; hypotarsus simple; ectotrochlear foramen in the form of a groove PODICIPEDIDCE xii. LIST OF W O R K S REFERRED TO OR CONSULTED. 1. BEDDARD, F. E.-Structure aud Classification of Birds, 1898. 2. BRANDT, J. P.-Beitrage zur Kenntn. der Naturgesch. der Vogel. Mem. Acad. Imp. des Sciences St. Petersb'ouro-ser. vi. vol. iii. 1839-40. s' 3. COUES, E - The Osteology of the Colymbus torquatus- with Notes on its Myology. Mem. Bost. Soc. Nat. Hist 'vol i part ii. 1867, pp. 131-172. ' " ' |