No. 535] THE SAUROPODOUS DINOSAURS 407 



bones of the legs were intended, according to Dr. Mat- 

 thew, to hold the animal down in the water, as the lead 

 in the diver's shoes holds him on the bottom. However, 

 it occurs to the present writer that if the sauropods 

 were accustomed to wade in water that came only a little 

 more than halfway to their backs the weight of the un- 

 submerged part of the body would suffice to hold them to 

 the bottom. A man who wades in water only waist-deep 

 does not need leaden soles. To maintain the theory, it 

 seems necessary to keep the reptiles more deeply sub- 

 merged. To do this it is only necessary to suppose that 

 they crawled about at the bottom of the water as croco- 

 diles do. If we suppose that the sauropods walked 

 wholly submerged and erect on four legs the differentia- 

 tion observed by Dr. Matthew in the ossification might 

 be explained on the supposition that it was for the pur- 

 pose of ballasting the animals. However, it does not ap- 

 pear that the hippopotamus, an eminent wader, needs 

 to be steadied in this way. Furthermore, why should 

 it have disturbed such facile swimmers as the sauropods 

 probably were to heel over occasionally? 



Notwithstanding the means employed by nature to 

 reduce as much as possible the weight of the skeleton, 

 the bodies of the sauropods were very heavy. The bones 

 of the legs were well-developed and I recognize that they 

 were not as hollow as those of a horse, for example. 

 Can we not, after all, most reasonably explain the case 

 by supposing that the sauropods went about more or 

 less on land and needed strong legs to hold up their 

 heavy bodies ! 



Tn my former article I expressed the opinion that it 

 was hardly possible for a diplodocus to walk about 

 wholly submerged. It appears that Cope and Osborn 

 and Matthew have thought that the animal would have 

 no difficulty in doing this. Perhaps the question can 

 never be definitely decided. The hippopotamus is said 

 to walk beneath the water and probably does really do 

 so; at least they remain for considerable periods be- 



