University of California Publications in Zoology [Vo 
13’. Total number of teeth 38. 
16. Greatest length of skull 16 millimeters or more. 
17. Sagittal crest well defined; rostrum broad (pl. 21, fig. 32). 
Myotis velifer 
17’. Sagittal crest not well defined; rostrum slender. 
18. Frontal region conspicuously inflated (pl. 21, fig. 35; 
and pl. 22, fig. 47); zygomatic breadth more than 
9.5 millimeters. Myotis thysanodes 
18’. Frontal region not conspicuously inflated (pl. 21, fig. 
34, and pl. 22, fig. 46); zygomatic breadth less than 
9.5 millimeters. Myotis evotis 
16’. Greatest length of skull less than 16 millimeters. 
19. Sagittal and occipital crests well defined (pl. 21, fig. 30, 
and pl. 22, fig. 42). Myotis occultus 
19’. Sagittal and occipital crests not well defined. 
20. Dorsal profile of skull distinctly flattened (pl. 22, fig. 
38). Myotis orinomus 
20’. Dorsal profile of skull not flattened. 
21. Occipital elevation distinct (pl. 22, fig. 40). 
Myotis longicrus longicrus 
Myotis longicrus interior 
21’. Occipital elevation not distinct. 
22. Interorbital constriction less than 3.5 millimeters. 
Myotis californicus californicus 
Myotis californicus quercinus 
Myotis californicus pallidus 2 
22’, Interorbital constriction more than 3.5 millimeters. 
23. Zygomatie breadth more than 8.5 millimeters; 
greatest length of skull more than 14 milli- 
meters. 
Myotis lucifugus altipetens 
Myotis lucifugus alascensis 2 
N 
ygomatic breadth less than 8.5 millimeters; 
greatest length of skull usually less than 14 
millimeters. 
Myotis yumanensis yumanensis 
Myotis yumanensis sociabilis 
Myotis yumanensis saturatus 
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