46 FOSSIL MAMMALIA OF THE 



" The croAvns of the teeth, encased in kistrous enamel, are long or high in proportion 

 to their breadth and thickness. They manifest this proportion, indeed, in a higher 

 degree than do the teeth of Spalacothermm ; and, being ronnded or cylindroid at the 

 aspect exposed, have suggested to me the generic name Stylodon, signifying ' pillar-tooth.' 

 The hindmost in place, supported apparently on a single columnar fang, which is partly 

 protruded from the socket, and covered with a darker and duller cement, has a longish 

 conical crown, with the fore part of the base rather more produced than the hind part : 

 the crown of the next tooth is somewhat longer : that of the antepenultimate has a 

 broader base, produced anteriorly into a minute angle, and slightly thickened behind, but 

 not developed into a continuous cingulum. The apical half of the crown is broken off 

 in the three teeth next in advance. Each has a small anterior basal ' talon,' and a single 

 columnar root, so far as it is exposed ; they are, likewise, severally smaller than the ante- 

 penultimate tooth. The seventh tooth, counting forward, is more abruptly smaller than 

 the rest, with a simple conical crown, indicating only a feeble prominence of the fore 

 part of the base. Then rises the crown of the largest tooth of the series, laniariform, 

 subrecurved, or seeming to be so, from the convexity of the front border, and the minor 

 concavity of the hind one, where the base is a little thickened and produced ; this crown 

 is supported on two divergent fangs. The convex surface of the jaw beneath these teeth 

 is entire — shows no neurovascular outlets — the main anterior one has gone with the 

 missing fore part of the ramus. 



" Any attempt to determine the nature of the above-described eight teeth must be 

 made on unsatisfactory and uncertain grounds. Guided by their shape and proportions, 

 we might view the foremost as a ' canine,' the next four as ' premolars,' the last three as 

 ' true molars,' and thus infer an example of placental diphyodont dentition. The 

 objection to the two-fanged character of the canine would be met by the same mode of 

 implantation of the canine of the common mole {Tal/pa), the proportion of which tooth to 

 the succeeding premolar is very similar to that presented by Stylodon. 



" But the proportion of the preserved dentigerous part of the present fossil to the 

 part behind indicates a greater number and size of teeth in advance of the laniariform 

 tooth than the three small incisors of Talpa. The closer similarity of the narrow 

 columnar hinder molars to those in the Cape Mole {Chrysochloris, Cuv.), and the very 

 probable addition of an eighth such molar to the seven in place behind the laniariform 

 tooth of the fossil, warn us of the deceptive character of the analogy of the dentition of 

 the common Mole. It is more likely that Stylodon like Spalacotherium and Chrysodiloris 

 (unique in this respect among existing Insectivora), exemplified that excess of number of 

 teeth which, in Marsupialia, as in Insectivora, is seen in a single known existing genus 

 {Myrmecob'ms), but was common in the similar small insectivorous pouched Mammals of 

 the older Oolitic deposits. Spalacotherium had ten molar teeth on each side of the lower 

 jaw, of which the last six had tricuspid crowns, with proportions and spacing similar to 



