part 1] DENTITION OF CLIMAXODUS WISEI. 3 



■comparatively well preserved on the opposing slab of shale (fig. 3,#). 

 These teeth are again about equal in size. As shown in oral view 

 (PL I, fig. 2 a), the apex of the crown has been well worn during 

 life to a slightly-convex lozenge-shaped face, of which only the 

 transverse long axis is formed by the highly- vascular dentine. The 

 .smooth anterior face of the root is exposed (fig. 2 b), and it is seen 

 to taper gradually downwards ; in the best-preserved specimen it 

 appears to be truncated below and somewhat less deep than wide. 

 The teeth of the single paired series flanking the prehensile symphy- 

 .sial teeth (fig. l)are much wider than the latter, with the elevation 

 of the crown reduced to a low ridge, to which the highly- vascular 

 dentine is restricted. This ridge is inclined forwards, and still 

 jDlaced so near the front of the crown that its comparatively deep 

 ■concave posterior face forms the greater part of the oral surface of 

 the tooth. The ridge is usually blunt, perhaps partly the result 

 of wear, but in one posterior tooth there is a trace of coarse ser- 

 ration at its ends. The basal imbrications are from five to eight 

 in number, and they are sometimes interrupted at the bluntly 

 rounded ends of the teeth. Nine of these teeth occur in undis- 

 turbed series on each side, diminishing in size forwards ; five are 

 behind the symphysial dentition, with their long axis inclined 

 slightly outwards and backwards. 



In the narrower dentition (PI. I, fig. 3), presumably lower, most 

 of the teeth are more imperfectly exposed, but nearly all seem to be 

 present. The space occupied by the prehensile teeth on the sym- 

 physis is actually wider than that in the opposing jaw, the flanking 

 blunt teeth being narrower. The back transverse row of the 

 symphysis (fig. 4) resembles that of the opposing jaw, except that 

 "the middle tooth of the three is larger. The next transverse row, 

 which is a little displaced and broken, comprises five teeth, of 

 which the middle one is much the largest, though smaller than that 

 behind ; the tooth of the inner paired series also much exceeds in 

 :size that of the outer paired series. The broken apex in these 

 teeth shows that the highly- vascular dentine is restricted to the 

 hinder face. The third row forwards again consists of five teeth, 

 .similar in structure and proportions to those of the second row, but 

 •all somewhat smaller. These are very much broken, and the teeth 

 of two still smaller transverse rows farther forwards, also evidently 

 consisting of one median and two paired series, are so much 

 battered that their precise characters cannot be determined. It 

 •can only be stated that the highly- vascular dentine is restricted 

 to a small patch in each. There is thus evidence of four transverse 

 rows of prehensile symphysial teeth in five antero-posterior series, 

 succeeded behind by one transverse row of three larger teeth. The 

 blunt teeth of the series flanking the symphysis are scarcely more 

 than half as large as those of the opposing jaw, but they are more 

 numerous, eight or nine bordering the symphysial teeth already 

 described, while four nearly similar teeth continue the series farther 

 back round a peculiar small constriction. Their characters are 

 ;not well shown (fig. 3); but they are transversely elongated, and 



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