Explanation of Plate XXXVIII. 



Figures i, 2, 3. — Skull oi Abrocoma ohlativa, sp. nov. (type), Yale Univ. Ost. Coll. 3320. 

 Natural size. 



Figures 4, 5. — Mandible of the same skull. Natural size. 



Figures 6, 7. — Skull of Agouti thomasi, sp. nov., Yale Univ. Ost. Coll. 3316. Natural size. 



Figure 8. — Mandible of Agouti thomasi, sp. nov., Yale Univ. Ost. Coll. 3326. Natural size. 



