Comparing a great chambered dinosaurian (_Camarasaurus_)
vertebra (see above) with the weight per cubic inch of an ostrich
vertebra, we reach the astonishing conclusion that it weighed only
twenty-one pounds, or half the weight of a whale vertebra of the same
bulk. The skeleton of a whale seventy-four feet in length has recently
been found by Mr. F.A. Lucas of the Brooklyn Museum to weigh seventeen
thousand nine hundred and twenty pounds. The skeleton of a dinosaur of
the same length may be roughly estimated as not exceeding ten thousand
pounds.
_Proofs of Rapid Movements on Land._ Lightness of skeleton is a
walking or running or flying adaptation, and not at all a swimming
one; a swimming animal needs gravity in its skeleton, because
sufficient buoyancy in the water is always afforded by the lungs and
soft tissues of the body. The extraordinary lightness of these
dinosaur vertebrae may therefore be put forward as proof of supreme
fitness for the propulsion of an enormous frame during occasional
incursions upon land[22]. There are additional facts which point to
land progression, such as the point in the tail where the flexible
structure suddenly becomes rigid, as shown in the diagram of vertebrae
below; the component joints are so solid and flattened on the lower
surface that they seem to demonstrate fitness to support partly the
body in a tripodal position like that of a kangaroo. I have therefore
hazarded the view that even some of these enormous dinosaurs were
capable of raising themselves on their hind limbs, lightly resting on
the middle portion of the tail.
Pages:
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112