x MONOGRAPHS OF NORTH AMERICAN RODENTIA. 



Series III.— HYSTRICOMORPHA: Hysteicise Rodents. 



Family VIII— CASTOEiOlDlD.E : (Fossil.) 



Pages. 



MONOGRAPH V.— Alien - 415-426 



Family IX.— IIVSTI4SOJD.E : Porcupines. 



M( INOGRAPH III.— Allen 379-398 



Suborder DUPLICIDENTATI : Leporine Rodents. 



Family X-LEPOKID.E : Hakes. 



MONOGRAPH II.— Allen 265-378 



Family XL-LACOMVIDJI: Pikas. 



MONOGRAPH IV.— Allen 399-414 



