564 
MR. TOMES ON THE STRUCTURE OF 
Fig. 9. A portion of a longitudinal section from the crown of a molar tooth of Sciuriis 
niger, showing, D, the dentine, and E, the enamel, with the fibres inter- 
spersed with irregular cells. 
Fig. 10. A longitudinal section from the fang of the same tooth, showing, D, the den- 
tine, and C, the cementum, in the outer portion of which the tissue is ar- 
ranged in rods, and is free from lacunae. 
Fig. 11. A portion of a longitudinal section from the crown of a molar tooth of 
Sciurus erythropus, showing, D, a part of the dentine with the tubes com- 
bined into E, a portion of the enamel. 
Fig. 12. A portion of a longitudinal section of an upper incisor of Arctomys pruhiosus, 
showing, D, the dentine, E, the enamel, with the lamellae leaving the surface 
of the dentine at a right angle, and F, the outer fibrous division of the 
enamel. 150 linear. 
Fig. 13. A transverse section from the same tooth, showing, D, the dentine, and E, the 
enamel. 
Fig. 14. A portion of a longitudinal section from the upper incisor of Castor Jiher, 
showing, D, the dentine with a peripheral layer of cells, E, the lamelliform 
portion, and F, the outer fibrous portion of the enamel. 
Fig. 15. A transverse section from tlie same tooth, showing, D, the dentine, E, the 
enamel, with the decussation of the component fibres of two laminae, and 
F, the outer part of the enamel. 
PLATE XLIV. 
Fig. 16. A portion of a longitudinal section from an upper incisor of Spalax typhlus, 
showing a peripheral portion of dentine with the downward direction of 
the branches of the dentinal tubes, and E, the enamel ; A, an oblique lon- 
gitudinal section, showing the fibres of alternate laminae divided trans- 
versely. 150 linear. 
Fig. 17- A transverse section from the same tooth; D, the dentine, E, the enamel. 
150 linear. 
Fig. 18. A longitudinal section from an upper incisor of a Dormouse {Myoxus avel- 
lanarius) ; D, peripheral portion of dentine, E, the enamel, showing the 
curved enamel lamellae and the fibres in the outer part of the tissue. 300 
linear. 
Fig. 19. An oblique longitudinal section from the same tooth, showing atE alternate 
layers of enamel fibres divided transversely with the intermediate ones 
exposed in their length. 300 linear. 
Fig. 20. A transverse section of the same tooth. 300 linear. 
