RODENTIA—MURINAE—REITHRODON LONGICAUDA. 451 
REITHRODON MEGALOTIS, Baird. 
Head and body from 2.50 to 3.00 inches; tail about two-tenths shorter. 
Above mouse-gray, lined with darker, and tinged with 
Sr. Cu.—Largest of North American species. 
Hind foot near .70. Ears large, moderately clothed with hair. 
rusty ; on the rump and sides a fulvous wash. Beneath, soiled yellowish white. 
Two specimens of Reithrodon were collected by Dr. Kennerly, between Janos, Sonora, and San 
Luis Spring, which I cannot readily refer to any of the described North American species. 
For a fuller account I would refer to the report of the United States and Mexican Boundary 
Survey. 
List of specimens. 
aE 3 ’ 
3 |4 g | Measurements. 
3 = 
= } oes g 
z/)e2 Locality. Whence obtained. a = — |Collected by— 
oe | ee iS From tip of nose to— /|Tailtoendof— Length of— | ° 2 
@ | Bo aoa | aea| Se 
z\£ 5 hes | | #2 | Bs 
& é E Eye. Ear. Occip.| Tail. | Verteb.| Hairs. peers Bipeee| ¢ - sg 
ae ee ee | = : = 
1039, 2281 | Janos to San Luis | Maj. W.H. Emory, | Mounted.)......)..000+) ceases 3.00 | 2.25] 2.30 |. sees. .68 -84 | .43 | Dr. C. B. Ken- 
Spring. U.S.A. | | | | nerly. 
1040}......|.... Gee sCOreswciscuis|(uceciea nels dO.seee esee| Inale....| .40 | 72 88 | 2.42) 2.25 | 30 +50 | ececes|seveeel vecscveces ove 
REITHRODON LONGICAUDA, Baird. 
Sp. Cu.—Size small. Tail considerably longer than the head and body, (which measure from 2.10 to 2.30 inches.) 
usually from three to eight tenths of an inch longer. 
tinged with reddish yellow 
Hind foot .65 to.70 of aninch. Above dark brown ; beneath white, 
A broad wash of bright fulvous on the sides and cheeks. 
This animal, in the character of head, ears, nose, and feet, is very similar to what has been 
described in Reithrodon humilis. 
larger. 
It is, however, of larger size, the ear and tail absolutely 
The tail is rather longer than the body, instead of shorter. 
The colors are very similar ; the back is a dark brown, rather darker than in the house mouse, 
but otherwise very similar. 
is a broad wash of fulvous extending to the cheeks. 
In some specimens, apparently younger ones, the belly approaches more to the 
The cheeks are, perhaps, brighter than in 
are white. 
whiteness of Hesperomys, though never attaining it. 
Rt. humilis. 
The belly is soiled white tinged with reddish yellow ; on the sides 
The feet, chin, and under parts of the tail 
The hind feet are considerably longer than in 2. humilis, in accordance with the 
increased length of the tail; these two members in mammals being usually in strict proportion 
to each other—the longer the tail the longer the hind feet, and vice versa. 
