292 XENOMYS, NEOTOMODON. 
stout; upper molars with three roots, lower with two; the series 
large, with flat crowns, and with rounded alternating closed triangles; 
first upper molar with one anterior and one posterior closed loop, and 
one external and two internal lateral closed triangles; second and 
third upper molars with one anterior and one posterior closed loop 
and one lateral closed triangle on each side; last lower molar deeply 
incised on inner face by a reéntrant angle; on outer side is an anterior 
and posterior-loop and a nearly closed triangle about the middle of 
the tooth; supraorbital beads well developed; lachrymals and inter- 
parietal large. 
296. nelsoni (Yenomys), Merr., Proc. Biol. Soc. Wash., vu, 1892, 
p. r6r, 
Netson’s Woop Rat, 
Type locality, Hacienda Magdalena, between City of Colima and 
Manzanillo, State of Colima, Mexico. 
Geogr. Distr. State of Colima, Mexico. 
Genl. Char. Size moderate; tail shorter than head and body. 
Skull resembling that of Neotoma, but differing in the characters 
given above. 
Color. Above fulvous, mixed with black on the back; orbital 
ring dusky; a white spot above the eye and one below root of ear; 
lips and fore part of cheeks white, rest of face fulvous; under parts 
creamy white; tail dark umber brown, unicolor; hands and feet 
whitish. 
Measurements. Total length, 300; tail vertebra, 143; hind foot, 
30; ear from crown, 18; from anterior root, 22. (Ear lengths from dried 
skin, others taken in the flesh.) Skull: occipito-nasal length, 40.6; 
Hensel, 33.3; zygomatic width, 32; interorbital constriction, 6; length 
of nasals, 14; palatal length, 19.3; length of upper tooth row, 8.6. 
Neotomodon Merr., Proc. Biol. Soc. Wash., xu, 1898, p. 127. Type 
Neotomodon alstont Merriam. 
Skull broad; braincase short; molars rooted, large, crowns flat; 
upper first and second molars with three external salient loops and 
two reéntrant angles; and two internal salient loops and one reén- 
trant angle; third upper molar small, rounded; lower first and second 
molars with three salient loops and two reéntrant angles externally 
