THE BIGGEST BEAST 87 



as an efficient working machine, though its limit of growth 

 is not determined by the same mechanical causes as those 

 which limit the bulk of the terrestrial quadruped. 



These considerations make it clear that we should 

 compare as to " bigness " terrestrial animals with other 

 terrestrial animals, and aquatic animals with aquatic ones. 

 It seems probable that Diplodocus was an aquatic 

 reptile, and never raised himself on to his four legs on 

 dry land as the Carnegie skeleton at the Natural History 

 Museum is doing. His legs and feet are quite unfitted 

 to support his weight on a land surface ; on land he 

 would have rested on his belly, as a crocodile does, 

 with much bent legs on each side. But submerged 

 in 20 ft. depth of water, he could have trotted along, 

 half-floating, with his feet touching the bottom and his 

 head raised on its long neck to the surface, slowly 

 sucking the floating vegetation into his moderate-sized 

 mouth. (See drawing on p. 91.) 



Diplodocus and Cetiosaurus have huge thigh-bones 

 and upper-arm bones respectively 5 ft. 9 in. and 3 

 ft. 2 in. in length until lately the biggest known limb- 

 bones, although the lower jaw-bone of a Right Whale 

 grows to be 18 ft. in length. But a thigh-bone (femur) 

 of a reptile similar to Diplodocus has been found in 

 Wyoming, 6 ft. 2 in. in length. This reptile was named 

 Atlantosaurus, and a cast of the huge bone the biggest 

 known when it was placed there stands in our museum 

 gallery. However, its glory has departed, for we now 

 know " than this biggest bone, a bigger still." The bones 

 of several individuals of a huge reptile similar to 

 Diplodocus, but actually twice as big in linear dimensions, 

 were found by Dr. Fraas at Tendagoroo, fifty miles from 

 the coast in German East Africa, and brought safely to 

 Berlin in 1912, though they have not yet been mounted 

 as a complete specimen. They were lying in a sandy 



