S2 



U.S. NATIONAL MUSEUM BULLETIN 2 75 



27 



26 



~ 25 



i 24 



23 



22 



21 



O Gerbillus henleyi 

 # Gerbillus kaiseri 



o 

 o o 



7 8 9 



LENGTH OF AUDITORY BULLA 



10 



Figure 14. — Comparison of length of auditory bulla relative to occipitonasal length of 

 Ccrbdlus henleyi and Gerbillus kaiseri. 



