368 HETEROMYS. 



The harsh pelage exhibited in Perognathus and Chcetodipus of 

 the Pocket Mice, is in the members of HETEROMYS carried farther, 

 even to the presence of small flattened spines in the fur. They are 

 animals of moderate size, with tails about equaling the head and 

 body in length, of various colorations, with a heavier skull, and 

 incisors smooth in front. Only one species is found north of the 

 Mexican boundary, but a number are natives of Mexico, Central 

 America, and the West Indies. They have a rather long, slender 

 body, and moderatel^ short legs. 



74. Heteromys. Spiny Pouched Rats. 



Heteromys Desm., Nouv. Diet. Hist. Nat. Mamm., 1817, p. 313. 



Type Mus anomalus Thompson. 

 Dasynotus Wagl., Nat. Syst. Amphib., 1830, p. 21. 

 Saccomys F. Cuv., Mem. Mus. Hist. Nat., Paris, x, 1823, p. 419. 

 Xylomys Merr., Proc. Biol. Soc. Wash., xv, 1902, p. 43. 

 Liomys Merr., Proc. Biol. Soc. Wash., xv, 1902, p. 44. 



Molars rooted; flattened spines mingled with the fur; skull almost 

 flat above, slightly arched in middle of superior outline; nasals 

 projecting beyond incisors; mastoids level with plane of occiput; 

 zygomata depressed, but not dipping to level of palate; occiput 



FIG. 69. HETEROMYS GAUMERI. 



No. 5844 Field Columbian Mus. Coll. Nat. size. 



UPPER TOOTH ROW. LOWER TOOTH ROW. 



Enlarged 8 times. Enlarged 8 times. 



