THE 



GEOLOGICAL MAGAZINE, 



NEW SERIES. DECADE V. VOL. V. 



No. VL — JUNE, 1908. 



Omca-IDST-iLIj -A.I?,TICI1.ES- 



I. — A lAEGE Labykinthodont Tooth from the Uppee Kaekoo 

 Beds of Wonderboom, neau Bukghersdoep. 



By Professor H. G. Seeley, F.R.S., F.L.S., F.G.S., King's College, London. 



(PLATE X.) 



rpHIS vomerine tooth was found by Dr. D. R. Kannemeyer when 

 1_ resident at Burghersdorp. It is the only evidence of the 

 dentition of the animal known, and is interesting as being of much 

 larger size than any Labyrinthodont teeth hitherto found in South 

 Africa, though smaller than the large teeth of Mastodonsaurus giganteus 

 from the Keuper of Wiirtemburg. Its presumed position on the palate 

 is based upon the anchylosis of the tooth with a bone which shows 

 a flat oblique suture at the base of the crown. This sutural surface 

 is usual on vomerine teeth, and indicates that the tooth was directed 

 downward, outward, and a little backward. 



The base of the crown is closed and convex, and appears to be 

 formed of dense tooth substance in which a labyrinthic structure is 

 visible. On one side of the base there is a smooth surface, convex 

 from above downward, concave from side to side, which is imperfectly 

 preserved. This surface extends on to the palate, and is an indication 

 of a vacuity, situated probably beneath an anterior nasal aperture. 

 The bone about the base of the tooth projects all round it as a slight 

 collar. 



The tooth is broken transversely, \\ inch of the length of the crown 

 is preserved in front, and little more than one inch on the hinder 

 border. The total length to the base is about 2 inches. This may 

 indicate, by approximation of the lateral curvatures, an original 

 length of 2|- inches. The base is transversely ovate, rather wider in 

 front than behind, and rather more convex on the outer than on the 

 inner side. But this irregular sub-triangular ovoid form is soon lost, 

 and at the superior fracture the tooth is circular, with a diameter of 

 more than half an inch. 



The external surface is marked with close-set fine linear ribs, 

 which are flattened and have a tendency to be gathered into bundles, 

 by the grooves from time to time becoming deeper, especially in 



DECADE V. VOL. V. NO. VI. 16 



