THE EESTORATION OF EXTINCT ANIMALS. 487 



up by Avater tb'- legs are not needed for locomotion, and ma}^ be very 

 small. 



Something, too, may be gathered from the structure of the leg bones, 

 for solid bones mean either a sluggish animal or a creature of more 

 or less aquatic habits, while hollow bones emphatically declare a land 

 animal, and an active one at that, and this in the case of the Dinosaurs 

 hints at predatory habits, the ability to catch and eat their defenseless 

 and more sluggish In-ethren. A claw, or better yet, a tooth, may con- 

 firm or refute this hint, for a blunt claw could not be used in tearing- 

 prey limb from limb, nor would a double-edged tooth, made for rend- 

 ing flesh, serve for champing grass. 



But few bones of the feet, and especially the fore feet, are present, 

 these smaller parts of the skeleton having been washed away before 

 the ponderous frame was buried in the sand, and the best that can be 

 done is to follow the law of probabilities and put three toes on the 

 hind foot and five on the- fore, two of these last devoid of claws. 

 The single blunt round claw among our bones shows, like the teeth, 

 that Triceratops was herbivorous; it also pointed a little downward, 

 and this tells that in the living animal the sole of the foot was a 

 thick, soft pad, somewhat as it is in the elephant and rhinoceros, and 

 that the toes were not entirel}^ free from one another. There are less 

 than a dozen vertebra, and still fewer ribs, besides half a barrelful of 

 pieces, from which to reconstruct a backbone 20 feet long. That the 

 ribs are part from one side and part from another matters no more 

 than it did in the case of the leg bones, but the backbone presents 

 a more difiicult problem, since the pieces are not like so many check- 

 ers, all made after one pattern, but each has an individuality of its 

 own. The total number of vertebrae must be guessed at (perhaps it 

 would sound better to say estimated, but it really means the same), 

 and knowing that some sections are from the front part of the ver- 

 tebral column and some from the back, fill in the gaps as best we 

 may. The ribs offer a little aid in this task, giving certain details 

 of the vertebra?, while those in turn tell something about the adjoin- 

 ing parts of the ribs. We finish our Triceratops with a tail of mod- 

 erate length, as indicated by the rapid taper of the few vertebra? 

 available, and from these we gather, too, that in life the tail was 

 round and not flattened, and that it neither served for swimming nor 

 for a balancing pole. 



So much for the manner in which, piece by piece, the framework 

 of an animal is put together, and what the various parts may tell 

 of the life and habits of some creature that long ago passed out of 

 existence. 



The basis of all reconstruction is, of course, the skeleton, and smce. 

 as said above, we can read the past only by the aid of the present, it 

 is absolutely essential to have a knowledge of the anatomy of creatures 



