Microtus californicus (Peale)
Fig. 37
Baculum: Stalk elongate, greatest length (3.0 mm.) 21/3 times greatest breadth, 4½ times greatest depth; median process ossified, ¼ length of stalk, basally broadened, flattened and shallowly grooved ventrally to fit tip of shaft, to which the process is closely appressed; lateral processes cartilaginous; ends of stalk bowed upwardly; posterior profile of base of stalk rounded or slightly trilobate if posterolateral concavities form in tuberosities; moderate development of tuberosities, in end-view dorsal concavity slightly deeper and narrower than ventral concavity, both comparatively shallow, median constriction 4/5 greatest depth; shaft curved, more or less terete at mid-point of stalk, terminally inflated dorsally; lateral profile in dorsal view gradually curved from point of greatest width anteriorly onto shaft.
Specimens examined: Two, of two subspecies; Microtus californicus californicus, 1 mi. NE Berkeley, in Contra Costa Co., California, 76828; Microtus californicus mohavensis, ½ mi. SE Victorville, San Bernardino Co., California, 63745.