380 Prof. II. G. Seeley on the Dentition of the 



original crown. The area of the pulp-cavity is occupied 

 with soft substance of the bluish-grey colour of the matrix, 

 which may possibly show a radial structure. The teeth thus 

 demonstrated increase in size posteriorly, where the diameter 

 is about -J^ inch. There may possibly have been as many as 

 four, but it is difficult to distinguish more than three, because 

 they are level with the surface of the jawbone. The inference 

 seems legitimate that these teeth originally possessed sharp 

 elevated conieal crowns, however unexpected it may be that 

 all the crowns should disappear during life so as to extend 

 the length of the diastema, leaving only polished dental 

 surfaces of the same height as the alveolar ridge, which holds 

 their roots. 



In Gomphognathus kannemeyeri the condition is so 

 dissimilar as to suggest a generic difference, for behind the 

 short mandibular diastema of T 4 inch the teeth are all of the 

 same stout type and contribute to form the grinding molar 

 surface, though only the middle part of the mandibular 

 armature is worn. They are similar to each other and not of a 

 kind to be easily broken, and are packed in the closest possible 

 succession. I have distinguished the first four as premolarsand 

 the remaining nine as molars, but there is no marked difference. 

 There are only nine functional maxillary molars in Gompho- 

 gnathus and allied genera, so that the thirteen teeth in tin; 

 mandible of G. kannemeyiri must either indicate that the series 

 is extended forward by teeth which are homologous with the 

 small decollated teeth now described, or that G. kannemeyeri, 

 the type of the genus, must be separated from the other 

 species. The former alternative is preferable, in the absence 

 of further evidence, but it requires that the premolars of the 

 young G. kannemeyeri should be classed in the same category 

 with the teeth in the diastema which are lost in this specimen. 

 They are probably a part of the first series of teeth without 

 masticatory function. 



The maxillary dentition is only known in Gomphognathus 

 po/yphagus. In the original description (Phil. Trans. Roy. 

 Soc. B, 1895, p. 18) the maxillary diastema is described as 

 raised a little above the palate and prolonged backward by 

 the curve of [six] small premolar teeth contained in a length 

 of half an inch. It is remarked that the first on the left 

 side appears to be worn down with use, but all the other 

 teeth on a level with the maxillary bones are broken or lost. 

 It is not possible now to determine whether the breakage 

 took place during life or during the removal of the matrix, as 

 seems probable. Their surfaces are certainly fractured by 

 the chisel, and in that respect are unlike the larger teeth in the 



