REPTILIA 223 



nium could not have weighed more than about two ounces, a brain 

 that even a two weeks' old kitten might be ashamed of. An elephant 

 of comparable size has a brain-weight of at least eight pounds. Curi- 

 ously enough the animal's real "brain," if we may call it such, is 

 situated near the base of its enormous tail, where there is a great sa- 

 cral enlargement of the spinal chord many times as large as the 

 dwarfed brain. Such a creature, with his brain in his rump, must 

 have been nothing but a bulky, ponderous automaton, driven by 

 stimuli arising in the lower nervous centers. 



The Ceratopsia were creatures whose proportions suggest those 

 of the rhinoceros. Triceratops (Fig. 128), a classic example of the 

 group, was about twenty-five feet in length and about ten feet in 



Fig. 128. — Restoration of the horned dinosaur, Triceratops. (From Lull, after 

 liohuchert.) 



height. The head was exceptionally massive, nearly eight feet in 

 length, with a wide frill-like expansion of the skull, which extended 

 like a shield over the neck and shoulders. On the front there were 

 three great horns, one on the snout and two above the eyes. Doubt- 

 less such creatures as these had as enemies the great carnivorous di- 

 nosaurs, for no other contemporaneous animals would have necessi- 

 tated such a defensive armament on the part of Triceratops and its 

 kin. The ceratopsians were strictly North American and lived for 

 only a brief span, geologically speaking; for they are confined exclu- 

 sively to the Upper Cretaceous. 



The Extinctioii of the Dinosaurs. — "One of the most inexpli- 

 cable of events" says Lull, "is the dramatic extinction of this mighty 

 race, for in the rocks of undoubted Tertiary age not a single 

 trace of them remains. One student has argued internecine war- 



