. The structure and life of birds . joints allowing the hinderpart of the back to the backbone ofmost birds that I have ex-amined bends downwardseasily, and through a con-siderable arc just in frontof the pelvis. The raisingof the hindmost ribs whichunite with the backbonebehind the point where thebend takes place, will aid the vertebral muscles instraightening the Wishing to test these conclu-sions by experiment, I suspended a freshly-killed pigeonby its wings, and inflated the air-sacks by means of ablowing-tube. The backbone a little in front of the 1 Other muscles assi
. The structure and life of birds . joints allowing the hinderpart of the back to the backbone ofmost birds that I have ex-amined bends downwardseasily, and through a con-siderable arc just in frontof the pelvis. The raisingof the hindmost ribs whichunite with the backbonebehind the point where thebend takes place, will aid the vertebral muscles instraightening the Wishing to test these conclu-sions by experiment, I suspended a freshly-killed pigeonby its wings, and inflated the air-sacks by means of ablowing-tube. The backbone a little in front of the 1 Other muscles assist. The levatores costarum, which I havefound highly developed in the domestic pigeon, arising from thevertebrae, then passing backwards and attaching to the ribs someway down, tend to make the upper part of the rib horizontal,thus broadening the chamber beneath. The triangularis sterni,which arises from the inside of the sternum, from its anteriorlateral end, attaches to the sternal rib-pieces, and tends to makethem 27. -B = , ext. intercostal;piece ; ST, sternum. T), dorsal rib ;S, sternal rib- 92 THE STRUCTURE AND LIFE OF BIRDS chap. thigh-joint moved rather more than half an inch, themovement of the sternum being almost too slight tomeasure. I do not wish to represent this experimentas one of much value. However, the conditions offlight were so far reproduced that the weight of thebody was hanging upon the wings and so hinderingthe movement of the breast while leaving the backfree ; it is true, there was none of the pressure—whichduring flight must be very great—of the wings uponthe coracoids and clavicles. But would not the onlyeffect of this pressure be to render the breastbone andthe bones united with it still less ready to move ?When a bird flies with his body sloping upward, ashe always does when he wishes to rise, I believe theprocess of breathing will be the same, with thedifference that the Latissimus Dorsi will not contractsufficient
Size: 1305px × 1914px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidstructurelif, bookyear1895
