50 THE AMERICAN MUSEUM JOURNAL 
CHRYSOCHLORIDA. 
Living. South Africa. 
These are known as Cape Golden Moles and take the place 
of the true Moles in South Africa. A fossil species has been 
found in the Miocene of Patagonia, indicating that they formerly 
inhabited both southern continents. 
ADAPISORICIDA, 
Extinct. Lower Eocene. France. Imperfectly known. 
DIMYLID2. 
Extinct. Lower Miocene. Europe. 
Only two molars in upper and lower jaw, the second quite small. 
Premolars reduced, no canine. Jaws are exhibited in the table-case. 
IV. RODENTIA, OR GNAWERS. 
Mice, Squirrels, Beavers, Hares, Porcupines etc. 
Small mammals with claws on the toes, five digits on each foot, 
the teeth reduced in number, a pair of upper and lower incisors special- 
ized for gnawing. The gnawing teeth grow continually from per- 
FIG. 24. _-SKULL OF THE RAT 
The most familiar type of the rodentia. Natural size 
sistent pulps, during the lifetime of the animal. They have enamel 
only on the anterior surface and wear to a chisel-like edge which is 
continually renewed by the more rapid wear of the dentine 
behind the enamel. 
The Rodents are the most numerous group of mammals, but 
they are almost allsmall. There are probably now more different 
