In D. o. compactus there is a complete enamel ring around the occlusal surface of each molariform tooth; in D. o. ordii this ring is incomplete lingually on each of the molariform teeth and labially on the first three, and in some individuals of D. o. sennetti the enamel ring is complete and in others it is incomplete labially and lingually as in D. o. ordii.
Specimens examined.—Total, 44, all from Texas, distributed as follows: Nueces County: 19 mi. S Port Aransas, Mustang Island, 27 (17 TCWC; 10 MVZ); Mustang Island, 17 (LACM).
Dipodomys ordii sennetti (Allen)
Dipodops sennetti Allen, Bull. Amer. Mus. Nat. Hist., 3:226, April 29, 1891.
Cricetodipus sennetti, Trouessart, Catalogus Mammalium, 1:581, 1897.
Perodipus sennetti, Elliott, Field Columbian Museum, Zool. Ser., 2:239, 1901.
Dipodomys ordii sennetti, [Davis], Journ. Mamm., 23:332, August 14, 1942.
Type.—Male, no. 3478/2733. Amer. Mus. Nat. Hist.; near Brownsville, Cameron County, Texas; obtained on March 9, 1888, by J. M. Priour. (After Allen, original description, type not seen.) Type locality recorded by [Bailey] (1905:145) as "Santa Rosa, 85 mi. SW Corpus Christi."
Range.—Southern Texas, south of Corpus Christi; marginal localities, all in Texas are: Somerset, 8 mi. NE Los Angeles, 8 mi. E Encinal, Santa Rosa, 28 mi. E Raymondville, 2 mi. S Riviera.