196 UN THE EXTINCT MAMMALIA OF 



A second jaw fragment, figure 27, from another young animal, but apparently the 

 same species, contains the entire last temporary molar and the first permanent molar. 



The latter has the same shape and constitution as the corresponding tooth of the 

 former jaw fragment, but it is slightly less robust, smoother, and has the intervals of 

 the lobes more open. Differences of the same kind ai'e observed between teeth of 

 diflerent individuals of recent sjDecies of Peccary. 



The temporary true molar has the usual construction, modified from that of the 

 permanent true molars, as observed in suilline animals generally. The crown is 

 formed of three pairs of lobes, of the same character but less well-developed than 

 those of the tooth behind. 



The measurements of the two lower jaw fragments and teeth are as follow : 



Thickness of jaw below second true molar, 

 Thickness of jaw below first true molar, 

 Antero-posterior diameter of second true molar, 

 Transverse " " " 



Antero-posterior diameter of first true molar. 

 Transverse " " " 



Antero-j)osterior diameter of last temporary molar, 

 Transverse " " " 



Antero-posterior diameter of last permanent premolar, 

 Transverse " " " 



Two specimens, consisting of the isolated crowns of molar teeth, apparently the 

 last of the upper series, probably belong to the same species as the jaw fragments 

 above indicated. One of the crowns is imperfect ; the other is represented in figure 

 26, and resembles in general appearance the last superior molar of the Peccary. 



The crown is low, and nearly as wide at its fore part as it is broad, but is abruptly 

 narrowed back of the middle. Viewed above it is trapezoidal in outline, with 

 rounded angles. It is surrounded by a basal ridge, thick in front and behind, thin 

 elsewhere, and interrupted a short distance at the bases of the internal lobes and the 

 postero-external lobe. All the lobes, tubercles, and ridges of the triturating surface 

 are strongly and vertically wrinkled. The anterior pair of lobes of the crown are 

 the best developed and most distinct. They appear as two conical hills with 

 furrowed sides, separated by a lower crescentoid ridge expanding in front of the 

 former, and embracing the antero-external hill. The crescentoid ridge is continuous 

 behind, with an oblique ridge crossing the transverse valley of the crown and be- 

 coming associated with the posterior lobes. The latter are less well-developed than 

 the corresponding elements in the Peccary, and are separated by a higher eminence. 



