NATURAL SCIENCES OF PHILADELPHIA. 181 



those of N. Jloridana, in rich rusty-red on the sides and partly 

 dusky metatarsus. 



To the foregoing list I append the description of an apparently 

 new species of this group: 



6. Hesperomys (Vesperimus) melanophrys, Coues, n. s. 



Syn. f ? Hesperomys mexicanus, De Sauss., R. M. Z. 1860, p. 00 (p. 20 of 

 reprint), pi. ix. figs. 1, la. 



Descr. from No. 10,183, Mus. Smiths., Sta. Efigenia, Sumichrast.' 

 General aspect of a species of the leucojnis group. Large ; nose 

 to eye 0.62 (inches and hundredths), to ear 1.12, to occiput 1.40, 

 to tail 4.15 ; tail 5.00 ; fore foot 0.42; hind foot 1.04; ear 0.T8 above 

 notch. Tail a little longer than head and body, slender, scant-haired* 

 Absolute and relative proportions of feet and digits as in V. leu- 

 cojnis ; soles hair^' on posterior third. Ears large, leafy, ap- 

 parently naked, really closely pilous. Whiskers reaching to or 

 beyond the shoulder. Skull strictly as in V. leucopuH (palate 

 ending opposite last molars, not far behind it as in Mus, Oryzomys, 

 etc.), but not quite so thin and papery, and developing a slight 

 bead on the orbital border, as in the stouter mice generally. 

 Color above giving the general impression of a gray mouse, rather 

 than a red mouse with darker dorsal area as in leucopiis and 

 aztecus. It is gra}', brightened with fulvous, slightly darker 

 along the back, more decidedly fulvous laterally, and everywhere 

 with a peculiar slight glaucous or hoary shade. Head noticeably 

 purer gray; eye encircled with a black ring in marked contrast, 

 the edges of the lids, and a little anteocular spot, being jet black. 

 (This suggests the specific name; I have seen nothing like it else- 

 where.) Color below, pure white, the plumbeous roots of the 

 hairs, however, giving a slight grayish cast. Line of demarcation 

 of this white with the color of the upper parts everywhere abrupt. 

 Outside of fore leg colored to the very wrist, but back of the hand 

 white. Hind leg also colored to and a little beyond the anklei 

 forming a definite dark spot on the base of the metatarsus, the 

 remaining five-sixths of the foot being pure white. Tail above, 

 like the back; below, gray not white; and the line of demarca- 

 tion, though evident, not sharp. No yellowish or fulvous tinge 

 anywhere on the under parts {^^ mexicanus''^ of De Saussure is said 

 to be yellowish on the chin and breast). Skull 1.20 long by 0.64 

 broad. 



