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.