458 REFERENCES TO THE PLATES. 



premolar, tlie first true moUir, :uul porlions ol" those succeeding, are restored from t!ie specimen of the 

 right side of the jaw. 



Fig. 2. Portion of the lower jaw, belonging to the .same individual as the jjreceding. It contains a 

 full series of teeth, Init the incisors have been introduced from the specimen of the opposite side. 



Fig. 3. View of the triturating surfaces of the upper teeth, mostly from the same specimen as figure 

 1, but partly from that of the opposite side. All arc observed to be much worn ; the incisors are 

 blunted ; the canine is most worn off posteriorly, and all the molars exhibit exposed tracts of dentine-; 

 least in the first premolar ; in the first true molar extending the entire breadth of the crown. 



Fig. 4. View of the triturating surfaces of the lower teeth, mainly from the same specimen as figure 2. 



Fig. 5. Last upper molar of the left side, from a_ difl^ereut individual than the preceding. It varies 

 from the corresponding tooth of the latter, as seen in figure 3, in being proportionately narrower and 

 in having a stronger posterior column. 



Figs. 6, 7. Inferior lateral incisor of the left side, from the same individual as the preceding speci- 

 men. Fig. 6. Outer view. Fig. 7. Inner view, in which is observed the exposed dentine of the worn 

 summit and postero-external border. 



Fig. 8. An upper lateral incisor of the right side. From a comparatively young animal, the tooth 

 being unworn. Outer view. The figure, Inadvertently, has been drawn In a reversed position. 



Fig. 9. The njij^er second and third premolars of the right side, apparently from the same individual 

 as the specimen of Fig. 8. a, second premolar ; b, third premolar. In the latter tooth, the postero-inter- 

 nal fossa of the crown and its included tubercles are not so well defined as in the corresponding tooth 

 of the specimen of Fig. 3. 



PLATE XI. 



All the figures are of the natural size. 

 Figs. 1-11. Merychyus elegans. See page 118, 



Fig. 1. View of the upper jaw and teeth. Taken from a specimen of the left side, reversed in the 

 figure to correspond with the next. 



Fig. 2. View of the right side of the lower jaw, from the same individual as the last. The canine 

 and first premolar are introduced from the opposite side. 



Fig. 3. View of the triturating surfaces of a series of upjDcr molars of the right side, including the 

 canine tooth. 



Fig. 4. Similar view of the teeth, which are more worn, taken from the same specimen as Fig. 1. 

 Fig. 5. View of the triturating surfaces of the lower molars of the left side, from the same indi- 

 vidual as those of Figs. 1, 2 and 4. 



Fig. 6. View of the triturating surfaces of the lower molars, except the last one, of the canine and 

 the lateral pair of Incisors, of the left side, from the same individual as Fig. 3. 



Fig. 7. Inner view of the lower molars and canine of the right side, from the same specimen as 

 Fig. 2. 



Fig. 8. Outer view of the canine and premolars, from the same individual as Figs. 3 and 6. 

 Fig. 9. Front view of the canine and incisors of the same specimen as the last. 



Fig. 10. Similar view of the canine and contiguous pair of incisors from the opposite side of the same 

 individual. The points of the Incisors are less worn than in those of the other side. 



Fig. 11. Front view of the upper canines and Incisors, from the same specimen as Fig. 1. 



Figs. 12-14. Mekychyus medius. See page 119. 



Fragment of the left side of the lower jaw, containing the true molars. 



