44 The Mammals of Colorado 
Type locality. — Unknown, probably from western Texas. 
Measurements. — Total length, 23.5; tail vert., 3.5; hind foot, 5.5; 
ear, 4.75-5.25. 
Description. — Upper parts gray with a slightly buffy tinge, 
usually darkened by a thin wash of black, sides of head and body 
grayer; a fairly well marked gray rump patch; ears decidedly 
longer than in L. melanotis, as is shown by the measurements given. 
One or two specimens from Coventry, Montrose County, taken in 
winter, are quite pale, but others, taken at the same place and 
season, are the usual color. There are no cranial differences to be 
noted between this form and melanotis, except somewhat larger 
bullae. 
Distribution. — The Texas Jack Rabbit is found north from 
northern Durango, Mexico, through Chihuahua, arid western Texas 
(except northern Panhandle), New Mexico (except northeastern 
part), northeastern Arizona, and southwest Colorado. Its vertical 
range is from 1,500 to 7,500 feet, and the zonal range mostly Upper 
Sonoran, but extending up into the Transition, and down into 
Lower Sonoran. 
The Colorado records are Bayfield and Fort Lewis, La Plata 
County; Ashbaugh's Ranch, Montezuma County; Norwood, San 
Miguel County; and Coventry, Montrose County. 
Genus SYLVILAGUS (Lat. sylva, a wood, + Grk. lagos, a hare, = 
wood-hare or rabbit). 
Sylvilagus Gray, Ann. Mag. Xat. Hist., 3d. Ser., xx., p. 221 
(1867). Type 5. nannus = sylvaticus = fioridaniis mallurus. 
Revision, Lyon, Smithsonian Miscell. Coll.., xlv., pp. 321-447 
(1904). Nelson, North American Fauna, No. 29 (1909). 
General characters and appearance similar to Lepns. Interparie- 
tal persistent as a distinct bone in adult; skull and teeth lighter 
than Lepvis; rostral portion wider than high ; postorbital processes 
united with the cranium behind (in old individuals), inclosing a 
narrow foramen; upper surface of skull much less pitted than in 
Lepus; skull much arched above, sometimes wider than one half its 
length ; head relatively larger than in preceding genus ; hind legs 
relatively shorter as referred to Colorado species ; pelage never turn- 
ing white in winter, and there is but one annual moult. 
The members of this genus are the small, thickset rabbits 
commonly known as "Cottontails." As the generic name 
signifies, they are, often at least, frequenters of woods and 
brushy places, though this is not invariably the case, as some 
