102 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
with them. The following table gives detailed measurements, and we are 
now enabled for the first time to state the length of the tail, which exceeds 
that of the head and body very decidedly, sometimes nearly one and a half 
inches. 
TaBLe XXVIII.—Mcasurements of six specimens of HESPEROMYS AZTECUS. 
From tip of nose to— ae cod Length of— 
= | Nature of 
re E 2 ature of specimen 
g Bocslity: 43 = ie ite |S and remarks. 
3 2 . o a = 
2 a 2 a ne 55 a 
| é a 3S Ee = 4 3 a oe! 
5 me 3S =) os o oF S is} o 
A R Slo Goes p = |e |A | & 
S906 Mexico s- ssa sce ee coy = = nent cera tet alee | meme BeflO} | sammie) | eae ae 0.38 | 0.90 | 0.62 | Dry; type. 
10325 | Cape Saint Lucas .-- h 298 | 1.15 |} 3. t I, r . 83 | 0. Alcoholic. 
10326 --do. 
10327 -. do, 
10328 ssostilt 
10329 Alcoholic; ungrown. 
10330 Alcoholic; suckling. 
HESPEROMYS (VESPERIMUS) MELANOPHRYS, Coues. 
Biack-eyed Mouse. 
? Hesperomys mexicanus, De Saussure, R. M. Z. 1860, 103, pl. ix, f. 1, la.* 
Hesperomys (Vesperimus) melanophrys, COURS, Proc. Acad. Nat. Sei. Phila. 1874, 181. 
(No. 10183.) With the general aspect of a large species of the Hesperomys 
leucopus group. Tail a little longer than the head and body together, slender, 
*“Velutinus, griseus, murinus; in lateribus paulum fulvescens, frequenter subferrugineus; subtus 
albidus, pectore et mento fulvescentibus ; pedes antici albidi; auricule permagne ; cauda corpore longior; 
mystaces elongati. 
“Intermediate in size between M. musculus and M. rattus. Pelage soft and velvety. Head conic, 
lengthened; lip cleft to the nose; muzzle hairy except the septum. Ears very large and broad, but higher 
than wide, rounded, but with the upper margin a little angular. Tail long, nearly equal to the head and 
body together, but sometimes only exceeding the body alone. Feet (‘ pattes’—more likely meaning limbs here) 
very long, especially the hinder, the animal standing high. Color, dark brownish mouse-gray (‘gris de 
souris brun-noiratre’), with a slight silvery shade on the back, the very tips of the hairs being yellowish- 
gray ; head not quite so dark; cheeks rusty-gray ; the yellowish always stronger onthe flanks. Feet, 
externally yellowish-gray (gris-fauve). Lips and chin pale yellowish-gray, and entire under parts gray- 
ish-white, apparently plumbeous, because the slaty roots of the hairs show through; the white distinctly 
separated from the color of the flanks. Breast and front of the shoulder washed with yellow. Fore feet 
white, or grayish; the hinder brown, with the ends of the tocs white. Ears apparently naked, but covered 
with short close hairs. Tail scaly, slightly hairy, black above, white below. Whiskers blackish, very 
long, reaching to or beyond the shoulders. 
“ Some individuals are yellower than as above; the sides becoming ferrugineous, strongly marked 
on the flanks at the line of separation between itself, the white of the belly here becoming almost pale 
orange. Sides and under surface of the head, as well as the shoulder and breast. strongly washed with 
rusty-yellow. In other specimens, on the contrary, the rusty color is not very evident. 
“ Length of one specimen, about 43, with tail 44; of another, about 4, with tail 34; hind foot slightly 
over one inch.” 
The foregoing is M. De Saussure’s diagnosis, with an abridged translation of his further descrip- 
tion; the chief points of discrepancy, as compared with our specimens of melanophrys, being italicized. 
It is inserted for convenience of comparison. 
