Microtus (Pitymys) quasiater (Coues)
Figs. 29 and 30
Baculum: Stalk broad, greatest length (2.6-3.2 mm.) 11/3 to 12/3 times greatest breadth, 31/3 to 32/3 times greatest depth; median process ossified, with ventral depression, process ¼ to 1/3 length of stalk, appressed to tip of shaft, wider than high proximally, relatively broad terminally; lateral processes cartilaginous, small, attenuate; posterior profile of stalk in dorsal view broadly rounded, bilobate, or trilobate, median lobe formed by posterior projection of dorsal shelf between enlarged lateral tuberosities that form outer lobes, posterolateral faces of these tuberosities visible in dorsal view of stalk; in end-view dorsal surface slightly concave, ventral concavity broad and deep, median constriction ½ greatest depth; shaft flattened except tip that is more terete, and bowed dorsally; at mid-point, stalk twice as wide as high; shaft relatively slender terminally, narrower than median ossification.
The baculum of M. quasiater is the largest and has the best developed base and median process of the three American species of the subgenus Pitymys. The three species closely resemble each other in basic form.
Specimens examined: Five, all from Veracruz; Teocelo, 4500 ft., 30709, 30711; 4 km. N Tlapacoyán, 1700 ft., 24466; 5 km. N Jalapa, 4500 ft., 19869, 19878.