FIGURE 1. Lower p3 enamel ultrastructure; Prolagus  aff. crusafoni from Popovo 3, cross-section.

figure1 

FIGURE 2. Posterior lobe of lower m2 enamel ultrastructure; Prolagus aff. crusafoni from Popovo 3, cross- section. 1-4, Enamel structure details from four different tooth parts.

figure2 

FIGURE 3. Lower p3 enamel ultrastructure; Ochotona  sp. from Popovo 3, cross-section.

figure3 

FIGURE 4. Lower m2 enamel ultrastructure; Ochotona  sp. from Popovo 3, cross-section.

figure4 

FIGURE 5. Upper incisor enamel ultrastructure; Ochotona  sp. from Popovo 3, cross-section.

 figure5

FIGURE 6. Lower incisor enamel ultrastructure; Ochotona sp. from Popovo 3, longitudinal section. 1-2, Enamel structure details from two different tooth parts.

 figure6

FIGURE 7. Lower p3 enamel ultrastructure; Ochotona  cf. eximia from Verkhnya Krynytsya 2, cross-section.

 figure7

FIGURE 8. Posterior lobe of lower m2 enamel ultrastructure; Ochotona cf. eximia  from Verkhnya Krynytsya 2, cross-section.

figure8 

FIGURE 9. Lower incisor enamel ultrastructure of Ochotona  cf. eximia   from Verkhnya Krynytsya 2, cross-section.

 figure9

FIGURE 10. Lower p3 enamel ultrastructure; Ochotona sp. from Lobkove, cross- section.

figure10