52 THE AMERICAN MUSEUM JOURNAL 
America. A tiny fossil Rodent, Meniscomys of the Oligocene 
epoch, is thought to be ancestral to it. 
FIG. 25 THE HORNED RODENT, CERATOGAULUS 
Skull and lower jaw. Middle Miocene of Colorado. Natural size 
MYLAGAULID2. Extinct. Miocene. 
Curious little Rodents with digging claws on the fore-feet, very 
wide short head and peculiar teeth. One skull in the case, the 
Ceratogaulus, or Horned Rodent, shows a large boss indicating a 
horn on the nose, which gives it an odd likeness to a rhinoceros 
skull. They are very rare fossils, found only in North America. 
CasToRID&. Beavers. Oligocene to Recent. 
Fossil Beavers of small size have been found in the Tertiary 
beds of both America and Europe and several skulls are shown 
in the collection. In the Quaternary beds are found remains of 
Beavers scarcely to be distinguished from the living species. 
