16 CONTENTS OF A BONE CAVE. 



containing the last two maxillary teeth, and having attached the adjacent portions 

 of the palatine bone. The maxillary bone projects between the last molar tooth a 

 distance equal to more than half the diameter of the latter. The palatine follows, 

 presenting some surface continuous with the external face of the maxillary ; its 

 maxillary suture pursues a nearly straight course forwards a short distance inside 

 the crowns of the teeth, It begins to curve inwards opposite the middle of the 

 penultimate molar, but continues some distance further forwards. The teeth 

 nearly resemble those already referred to the A. inundata, but are considerably 

 larger. The first molar of the left maxillary which accompanies the other pieces, 

 is also materially different in form from the corresponding tooth of that species. 



The first superior molar includes four dentinal columns, of which the posterior 

 is much the smallest, and is situated on the inner angle of the posterior face of the 

 tooth. The enamel bands are directed a little backwards as well as outwards, and 

 the one between the first and second columns has an inflexion near its inner ex- 

 tremity. The anterior external enamel plate is regularly convex in section and 

 oblique in position, striking the dividing plate which follows it at a point on the 

 outer side of the crown which marks the middle of the long diameter. In the 

 A. inundata the corresponding tooth is not only very much smaller but is relatively 

 narrower in transverse diameter, and the anterior column does not extend so far 

 backwards on the outer side. This tooth is, in the A. latidens, as large in all its 

 diameters as the third or fourth molars. 



The second molar is wanting from the specimen, but its alveolus shows that its 

 posterior wide columns project further inwards than in either of the teeth which 

 follow. The grinding surface of the third superior molar is straight on the inner 

 side and convex on the outer through the prominence of the second and third col- 

 umns ; the fourth is small and internal. The anterior column of the fourth molar 

 is more transverse than the others or than those of the third, which are oblique. 

 The inner side of the grinding face of the tooth is longer than the outer, owing to 

 the presence of the small fifth column. 



A pair of incisors with both extremities wanting, which are held together by the 

 matrix, accompanied the above specimens. They belong to the upper jaw, and as 

 they are of appropriate size to the superior molars just described, I suspect that 

 they belong to the same animal. Their section is triangular, with the external 

 anterior margin projecting and curved with an incurved border of the enamel sheet. 

 The surface of the latter is marked with numerons irregularly spaced longitudinal 

 grooves, excepting for a narrow space along the inner margin, which is smooth. 



MEASUREMENTS. 



If. 



Length of first molar ..... -033 



~. r T r < r ( fore and aft . .018 



Diameter of grinding face of first molar 



(.transverse . . .(Jl<> 



(fore and aft . .015 



of third molar J. 



(.transverse . . .015 



, (fore and aft . . .017 



of fourth molar < 



(transverse . . .014 



,,.,.. ... (fore and aft . . . .017 



of shaft of superior incisor < ,.. 



(.transverse . . . .017 



