Remarks.—This subspecies retains its chief diagnostic character, blackish mid-dorsal region, throughout nearly all parts of its range. Specimens from the general area of Matagorda Bay and Lavaca County grade into taylori in characters of color and crania. The Colorado and Brazos rivers seemingly serve as barriers reducing gene flow between taylori and subater. These rivers may well have been important factors in the origin and the limitation of these two seemingly closely-related subspecies.

Baiomys taylori subater is not differentiated in color of pelage and characters of crania from B. t. taylori to the same degree that B. t. paulus is differentiated from B. t. analogous, or that B. t. taylori is differentiated from several of the other subspecies of Baiomys taylori. B. t. subater probably is a more recent occupant of the area in which it now lives than is the case with any other one of the subspecies of taylori. Sufficient time probably has not elapsed to allow for formation of more distinctive phenotypic patterns.

Specimens examined.—Total 65, all from Texas and distributed as follows: Brazos County: 1/2 mi. NW College Station, 1[55]; 3 mi. W College Station, 1 mi. W Easterwood Airport, 1[55]; College Station, 1[55]. Walker County: Huntsville, 1[55]. Hardin County: Sour Lake, 1[57]. Jefferson County: 7 mi. S Labelle, 10. Harris County: 6 mi. NE Crosby, 1[56]. Colorado County: 10 mi. N Eagle Lake, 1[55]; 9 mi. N Eagle Lake, 1[55]; 2 mi. W Eagle Lake, 1; Eagle Lake, 1[55], 5. Fort Bend County: Richmond, 4[57]. Galveston County: Texas City, 6[58]; Virginia Point, 1[57]. Brazoria County: Austin Bayou near Alvin, 2[57]; 14 mi. SSE Alvin, 2[59]; type locality, 7[57] (including the type). Lavaca County: 4 mi. W Hallettsville, 1[55]; 1 mi. SW Hallettsville, 3[55]; 13.7 mi. SW Hallettsville, 2[55]; 4 mi. NE Yoakum, 11.

Marginal records.—Texas: Huntsville; Sour Lake; 7 mi. S La Belle; Virginia Point; 14 mi. SSE Alvin; type locality; 4 mi. NE Yoakum; 4 mi. W Hallettsville; 1/2 mi. NW College Station.

[55] Texas A & M, Cooperative Wildlife Research Collection.

[56] Carnegie Museum.

[57] U. S. Nat. Museum (Biol. Surv. Coll.).

[58] Los Angeles County Museum.

[59] American Museum of Natural History.