CRKTACEOUS VERTEBRATE FOSSILS. 



517 



angular and surangular bones are, however, quite short and not especially 

 strong. 



The teeth of Claosaurus are routined entirely to the maxillary and 

 dentary bones. In each, the teeth are very numerous and are arranged in 

 vertical series, so that they succeed each other as the functional teeth are 

 worn away. This is seen in fig. 82, which shows the form of the teeth and 

 their relations to each other in the same series. The number of teeth in 



Skull otdlaosav 



ens Marsh ; se 



Fto. 82.— Series of riv 

 c crater view. 



I'-t'ih "f t'hiumiiriix auncctens. One-half natural 



each series depends upon the position, those near the middle of the jaw 

 having the greatest number, sometimes six or more. The teeth of the 

 upper jaw have the external face of the crown covered with enamel and 

 ridged. In the lower jaw this is reversed, the ridged face of the crown 

 being on the inside. This arrangement greatly increased the cutting power 

 of the jaws. The food was probably soft vegetation. 



