PROC US. NAT. MUS. VOL. 110 



HERSHKOVITZ, PLATE 4 



Upper and lower molars (X 10) of same specimens (except as noted) shown in plate 3: a, 

 Oryzomys bicolor (CNHM 18541); h, 0. concolor; c, 0. palustris; d, Rhipidomys venustus. 



