No. 535] THE SAUROPODOUS DINOSAURS 409 



dealing here with animals that are supposed to have the 

 whole, or at least nearly the whole, of the weight taken 

 from their limbs. 



Moreover, does not the one part of Dr. Matthew's 

 theory contradict the other? He has told us that the 

 parts of the skeleton below the water-line were heavy 

 for the purpose of overcoming the buoyant effect of the 

 water, as the lead in the diver's shoes does. Then, as 

 shown in the preceding paragraph, he maintains that 

 there was pressure enough to produce such legs as the 

 elephant has, an animal whose legs must support its 

 whole weight. 



We may now be permitted to inquire whether or not 

 aquatic life is likely to have produced either of the ef- 

 fects attributed to it by Dr. Matthew. The hippopota- 

 mus is an animal far less aquatic than Cope and Osborn 

 and Matthew have supposed the sauropods to have been. 

 Its limbs are almost ridiculously short, so short that 

 when it is quitting or entering the water its belly leaves 

 broad and deep channels in the mud through which it 

 wades. The leg bones are indeed very strong, a result 

 conditioned by the frequent excursions made on the 

 land. The feet are the most primitive possessed by any 

 living artiodactyl, and the digits are bound together by 

 a short web. The aquatic performances of the tapir have 

 not contributed to its structural uplift, for its feet are 

 among the most primitive of those of the perissodactyls. 

 Let one only view with some attention a series of 

 mounted skeletons and one will soon be struck with the 

 fact that degenerative changes begin to affect the limbs 

 of animals very shortly after they begin to confide to the 

 water the support of their bodies; and these degenera- 

 tive modifications continue to manifest themselves until 

 the limbs have been converted into paddles and flippers 

 or reduced to vestiges or even extirpated. 



That the sauropods had originally been amphibious 

 and then became strictly aquatic seems to the writer 

 highly improbable. Those short digitigrade feet, with 



