A CHAT WITH PROF. COPE CONTINUED. 369 



The muzzle was shorter and deeper than that of a 

 bull-dog. The teeth were all sharp cylindric fangs, 

 smooth and glistening, and of irregular ' size. At 

 certain distances in each jaw they projected three 

 inches above- the gum, and were sunk one inch into 

 the bony support, being thus as long as the fangs 

 of a tiger, but more slender. Two such fangs crossed 

 each other on each side of the middle of the front. 

 This fish is known as Portkeus molossus (Cope). Be- 

 sides the smaller fishes, the reptiles no doubt sup- 

 plied the demands of his appetite. 

 1 The ocean in which flourished this abundant and 

 vigorous life, was at last completely inclosed 'bn the 

 west, by elevation of sea-bottom, so that it only com- 

 municated with the Atlantic and Pacific at the Gulf 

 of Mexico and the Arctic Sea. The continued eleva- 

 tion of both eastern and western shores contracted 

 its area, and when ridges of the sea-bottom reached 

 the surface, forming long low bars, parts of the 

 water area were inclosed and connection with salt 

 water prevented. Thus were the living beings im- 

 prisoned and subjected to many new risks to life. 

 The stronger could more readily capture the weaker, 

 while the fishes would gradually perish through the 

 constant freshening of the water. With the death 

 of any considerable class the balance of food supply 

 would be lost, and many larger species would disap- 

 pear from the scene. The most omnivorous and en- 

 during would longest resist the approach of starva- 

 tion, but would finally yield to inexorable fate; the 

 last one caught by the rising bottom among shallow 



