CHAPTER V.

FOSSIL RODENTIA.

Families of Rodents represented by Fossil Remains--State of the “Record of the Rocks”--THE SCIURIDÆ--Sciurine Genera now Extinct--No Fossil ANOMALURIDÆ and HAPLODONTIDÆ--ISCHYROMYIDÆ--_Pseudotomus hians_--_Gymnoptychus_--CASTORIDÆ--Mr. Allen’s CASTOROIDIDÆ--THE MYOXIDÆ--No Fossil LOPHIOMYIDÆ--THE MURIDÆ--THE SPALACIDÆ--THE GEOMYIDÆ--THE DIPODIDÆ--THE THERIDOMYIDÆ--THE OCTODONTIDÆ--THE HYSTRICIDÆ--THE CHINCHILLIDÆ--THE DASYPROCTIDÆ--THE CAVIIDÆ--THE LEPORIDÆ--THE LAGOMYIDÆ--_Mesotherium cristatum_--Difficulties concerning it--Mr. Alston’s Suggestion--THE HEBETIDENTATA--Teeth--Skull--Skeleton--Conclusions regarding it--Table of Rodent Families--Concluding Remarks 151

ORDER EDENTATA, OR BRUTA (ANIMALS WITHOUT FRONT TEETH).