Peromyscus boylii

Excerpts: Peromyscus maniculatus. - Incisor base capsule always to moderately well developed; anteroconid usually not divided (79% Grade 0); stylids and lophids uncommon to rare (14% and 7%, respecitively).

Peromyscus boylii. - Incisor base capsule always Grade 0; anteroconid divided in about half the jaws, but usually not deeply so; stylids present in about a third (29%) of the jaws but lophids usually absent.

Reference

Dalquest, W. W., and F. B. Stangl, Jr. 1983. Identification of seven species of Peromyscus from Trans-Pecos Texas by characters of the lower jaws. Occasional Papers, The Museum, Texas Tech University, no. 90:1-12.