When Setzer (Univ. Kansas Publ., Mus. Nat. Hist., 1:473-573, December 27, 1949) reviewed the subspecies of _Dipodomys ordii_ he lacked specimens of _Dipodomys ordii compactus_ from the type locality or from anywhere else on Padre Island. He used as representative of _D. o. compactus_ specimens from Mustang Island, Texas, the island next northeast of Padre Island. Through the courtesy of Mr. Stanley P. Young, Dr. Hartley H.T. Jackson and Miss Viola S. Schantz, of the United States Biological Surveys Collection, I have examined topotypes of _D. o. compactus_ from Padre Island. This examination discloses that the kangaroo rats on Padre Island and Mustang Island are significantly different. Those from Mustang Island may be named and described as follows: MEASUREMENTS (IN MILLIMETERS) OF ADULT MALES OF FOUR SUBSPECIES OF DIPODOMYS ORDII Key: A Total length F Breadth across maxillary arches B Length of tail G Width of rostrum C Length of hind foot H Length of nasals D Greatest length of skull I Least interorbital width E Greatest breadth across bullae J Basilar length ---------------------------------------------------------------------- _D. o. largus_, type locality (K.U.) A B C D E F G H I J Mean (9) 226 117 35.8 36.3 21.5 19.2 3.6 13.7 12.6 23.2 Maximum 241 128 37 37.2 22.0 19.9 3.7 14.2 13.9 23.9 Minimum 212 105 35 35.2 20.7 18.6 3.5 13.5 11.6 22.3 ---------------------------------------------------------------------- _D. o. compactus_, type locality (U.S.N.M.) A B C D E F G H I J Mean (10) 230 126 37.7 36.6 22.1 20.0 3.8 14.0 12.5 23.8 Maximum 241 135 40 37.8 23.2 21.4 4.0 14.5 13.1 24.4 Minimum 208 118 35 35.5 21.6 19.2 3.6 13.1 11.3 23.1 ---------------------------------------------------------------------- _D. o. parvabullatus_, type locality and 2 mi. S of same (K.U.) A B C D E F G H I J Mean (7) 216 111 35.9 36.4 21.7 19.6 3.6 13.8 12.1 23.0 Maximum 222 113 37 36.9 22.1 20.7 3.8 14.2 12.5 23.5 Minimum 210 109 34 35.9 21.3 19.1 3.3 13.4 11.6 22.1 ---------------------------------------------------------------------- _D. o. sennetti_, 2 mi. S Riviera, Texas (after Setzer, op. cit. :565) A B C D E F G H I J Mean (5) 218 112 35.8 37.2 23.4 20.1 4.0 13.6 13.1 24.2 Maximum 222 115 38 38.2 24.1 20.7 4.3 14.4 13.2 24.6 Minimum 208 104 34 36.3 23.0 19.4 3.8 13.0 12.6 23.8 ---------------------------------------------------------------------- Dipodomys ordii largus new subspecies Ord Kangaroo Rat