. The structure and life of birds . |; Nestor Parrot 4 Red-throated Diver . . iSpur-winged Goose .... 1,^5 These measurements speak for themselves, evenwithout any exact statement of the weights of thebirds ; but the following illustration will do more toexplain the problem of hollow bones. The shoulderbones of a Skua Gull, which has scarcely any aeration,of a vociferous Sea Eagle, and a Hornbill, both of whicharc highly pneumatic, arc placed side by side. The VI FORM AND FUNCTION in greater girth of the hollow bones in proportion to theirlength is at once obvious. But to bring this out stillm
. The structure and life of birds . |; Nestor Parrot 4 Red-throated Diver . . iSpur-winged Goose .... 1,^5 These measurements speak for themselves, evenwithout any exact statement of the weights of thebirds ; but the following illustration will do more toexplain the problem of hollow bones. The shoulderbones of a Skua Gull, which has scarcely any aeration,of a vociferous Sea Eagle, and a Hornbill, both of whicharc highly pneumatic, arc placed side by side. The VI FORM AND FUNCTION in greater girth of the hollow bones in proportion to theirlength is at once obvious. But to bring this out stillmore clearly, I have taken the wing bones of the Skua. Humerus of Pomatorhine Skua ((?) ; Rhinoceros Honibill (i) ; and Vociferous SeaEagle (c). Drawn to scale. as the standard, and calculated what would have beenthe length of the same bones and of the whole wing inthe Sea Eagle and the Hornbill, if they had been builtupon the same lines ; 112 THE STRUCTURE AND LIFE OF BIRDS chap. Girth ofHumerus. Humerus. Aggregate Length ofWing Bones. Skua Sea Eagle . .Rhinoceros Hornbill ActualLength. 1 Length pro- , , , I^f ^ P;;uortionate Actual portionate ito Girth. Length. to Girth of :1 ; Humerus. |4 inches 1 4I inchesif „ 4-1 ., 4i inches: 13^ I3i 7^ ,, 1 20-,^ 22^7A „ \ I5i 23i| Thus, if in the Sea Eagles humerus length wereproportioned to girth, the bone would be more thanhalf an inch longer ; on the same principle the aggre-gate length of the wing bones would be greater by morethan one and a half inch ; the Hornbills wing wouldbe lengthened by more than eight inches, its humerusby more than three ! If now we take a fine saw andcut the hu
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1895
