DIC0TYL1N.E OF AMERICA. '■'■'•' 



late. Between the lobes externally it forms a small simple tubercle. Internally, in the 

 on, ii ia hardly developed, except in the last molar, where it is also a simple 

 tubercle. In the latter tooth posteriorly on each side of the fifth lobe, it is constituted by 

 a simple tubercle. 



The superior deciduous molars preserved in the cave head, (PI. 37, fig. 17,) regularly 



deer ase in size from the permanent true molars to the first of the former. The third and 



second superior deciduous molars closely resemble the permanent teeth behind, except that 



the anterior part of the crown of the Becond is narrower. The first deciduous molar pos- 



- bul a single transverse pair of tubercles, and its crown is trilateral. 



From the trituration to which the deciduous teeth have been subjected, trefoil-like tracts 

 of dentine arc exposed upon the inner lobes, and simple transverse oval ones upon the 

 summits of the outer lobes. Judging from the wearing of these teeth, the relative 

 length of the lobes of the permanent molars, and the depth of their intervening valleys, the 

 movements of the lower ja^ in the animal to which the cave head belonged, were rather 

 more restricted ginglymoid in their character than in Dicotyles, but perhaps in a less dc- 

 -• than in Platygonus. 



In the Peccary the superior premolars (PI. :!?, figs. 1, 2,) still present the same general 

 construction as the true molars. The posterior two present very distinctly the lour cha- 

 racteristic wrinkled conoidal lobes, but the postero-internal is reduced in size in the third 

 premolar, and is very feebly developed in the second. The crown of the first is trilateral, 

 and Btill | four distinct tubercles, but only one is strikingly prominent. 



In the cave head, the three superior permanent premolars, (PI. iJT, figs. •"">. <>.) present each a 

 transverse pair of permanent lobes like those of the true molars, surrounded by a basal ridge. 



The Litter anteriorly and posteriorly is very thick and denticulate at the margin. In 

 the posterior two premolars the hinder portion encloses four small irregular fovea? with 

 wrinkled sides, the anterior portion two similar but larger foveas. In the first premolar 

 the basal ridge forms a cup with wrinkled sides, from the bottom of which project the 

 two characteristic lobes. 



The inferior premolars PI. 37, figs. 7, 8,) of the cave hi ad resemble those of the D.torqua- 

 Pl. 37, figs. 3, 4,) with the principal lobes much exaggerated. They decrease successive!) 

 anteriorly, and are much more oeai Ij equilaterally quadrate than in the Peccary. The pos- 

 terior two premolars of the fossil are more like the second than the third of the Peccary, but 

 are relatively broader. Each has a transverse pair of principal lobes, ver) long and shaped 

 like those of the true molars, and bounded behind by a \<t\ thick basal i rising in 



an antero-posterior prominence al the middle, and enclosing on each side of the latter ;i 

 large fovea with wrinkled sides. Anteriorly, also, the basal ridge exists, but is feeble, 

 whether contrasted with the posterior portion or that corresponding to it in the D. tor- 

 quatus. The lir-t premolar is square, or relative!) very broad contrasted with that of the 

 i'. i cary, and the basal ridge forms a cup with wrinkled Bides, out of the bottom of which 

 a transverse pair of short conoidal loins. 



In Dicotyles the exserted portion of the upper unworn canine is enveloped in enamel, 

 sing by a sinuous margin al it base and deeplj notched anteriorly. The inferior 



