282 



developed behind into a low talon, and interrupted at the outer end and more so at 

 the inner end of the two main lobes, and for a greater extent at the inner than at the 

 outer sides : this character my present series shows to be constant. 



The horizontal contour of the crown of the penultimate molar is rather rhomboidal 

 than quadrate; for the hind lobe is more internal in position than the front one, and 

 the ridges run, not in a line directly across the alveolar border, but from without 

 inward and a little backward. The fore part of the outer end of each ridge is a little 

 produced, most so in the hinder one, in which the produced part inclining inward, 

 terminates or abuts below upon the middle of the base of the front ridge : the anterior 

 part of the inner end of each ridge is a little produced forward, in an angular form ; 

 the general result is that the summit of each ridge is slightly concave forward, convex 

 backward. 



The g amel is for the most part smooth and polished ; the delicate stria? of growth 

 are well marked when viewed by a pocket-lens on the outer side of the tooth, and the 

 same power brings into view a few punctations on the hinder slope of each ridge : the 

 enamel is rather thicker on this slope than on the front' one, and seems more so from 

 being more obliquely abraded from before downward and backward : so exposed, the 

 coronal surface of the enamel is a line in thickness ; the tract of dentine abraded in the 

 present tooth is two lines across. The hinder talon, or part of the cingulum, is most 

 developed ; the front one seems as if destroyed by pressure of that of the preceding 

 molar. 



Much of the crown of the last molar (ib. m 3) has been broken away ; its base measures, 

 in fore-and-aft extent 1 inch 10 lines, in transverse extent 1 inch 3^ lines ; this is at the 

 anterior lobe, the posterior one is narrower. Each fang is longitudinally excavated at 

 the surfaces next each other ; and the outer part of the root, so denned, is thicker than 

 the inner part. 



The next stage of dentition which I have had the opportunity of observing in an 

 original specimen of the present species corresponds with that of the maxillary teeth 

 in the skull (Plate XXVII. fig. 3) ; it is exemplified in the mandible which is the subject 

 of Plate XXXVIII. The crown of the last molar (Plate XLIV. figs. 1 & 2, m 3) is 

 worn to within three or four lines of the transverse valley ; those of the penultimate (m 2) 

 and antepenultimate (m \) molars show increasing degrees of attrition : the first and 

 second molars are gone, but their sockets remain in the left ramus : the crowns are 

 restored in outline, in fig. 1, from the subject of Plate XL. 



The anterior fang of the first molar remains in the corresponding division of its 

 socket : the fore-and-aft extent of the socket is 1 inch, being 3 lines more than in the 

 young specimen (Plate XL. figs. 1 to 5, d 3). Now, as the roots of the first molar in that 

 specimen are hollow shells of bone widening to their open base, the crown of the tooth 

 may gain increase of support, by enlargement of the fangs before they become solidified, 

 as in the broken one in the present specimen. The difference of size may likewise be 

 referred to difference of sex ; it would be hazardous to predicate a difference of species 



