Nelson (N. Amer. Fauna, 29:194-195, August 31, 1909) described specimens from the Big Bend area of Texas. This was the only area from which Nelson had specimens. Our examination of these same specimens indicates that his description of them was accurate. Davis and Robertson (Jour. Mamm., 25:271, September 8, 1944) recorded a specimen, under the name _Sylvilagus robustus_, from "The Bowl, Guadalupe Mountains, Culberson County, Texas." Our examination of the skull of this specimen ([female] adult, No. 658, Mus. Zool., Louisiana State University) indicates that it is, among named kinds of rabbits, best referred to _robustus_. The specimen is morphologically as well as geographically intermediate between _S. f. cognatus_ and _S. robustus_. This morphological intermediacy is illustrated by certain of the following cranial measurements of three adult females: No. 108695 (_robustus_), Chisos Mts.; No. 658 from the Guadalupe Mts.; and No. 128651, NE slope Capitan Mts. Basilar length, 59.2, 54.2, 54.4; length of nasals, 33.9, 31.1, 32.2; breadth of rostrum above premolars, 19.3, 17.5, 17.0; depth of rostrum in front of premolars, 15.8, 14.8, 14.0; interorbital breadth, 20.4, 19.1, 19.7; parietal breadth, 27.2, 27.1, 26.5; diameter of bulla, 13.3, 12.2, 10.7. Considering the intermediate nature of specimen No. 648, and the kind and amount of difference between _Sylvilagus floridanus cognatus_ and _S. robustus_, it seems appropriate to us to use the name-combination _Sylvilagus floridanus robustus_. Actual intergradation, in the sense of interbreeding between individuals of a continuously distributed population of animals, probably does not occur regularly between _S. f. cognatus_ and _S. f. robustus_ nor between several populations within either one of these subspecies; in south-central Arizona and western Texas the animals are said to occur only in the higher parts of the mountains. Consequently a given population is separated from another by low-lying territory inhospitable to the species _Sylvilagus floridanus_. This low-lying territory is inhabited by another species, _Sylvilagus audubonii_. More intensive collecting in the region concerned may, however, show a continuous distribution of the species _Sylvilagus floridanus_ in several areas where it seems now to have an interrupted distribution. Sylvilagus audubonii neomexicanus Nelson 1907. _Sylvilagus audubonii neomexicanus_ Nelson, Proc. Biol. Soc. Washington, 20:83, July 22.