200 Orcen — New Purbeck Mammal. 



flatness suggestive of marsupial afiinities ; but the angle itself is 

 broken off. As, bowever, tbe alternative is the almost equally low 

 " lessencepbalous " sub-class, to wbicb tbe present little insectiovore 

 must be referred, if it be not " lyencepbalous," it adds anotber to tbe 

 prevalent testimony of tbe low condition of Mesozoic mammalian 

 life. 



Tbe crowns of tbe teetb, encased in lustrous enamel, are long or 

 bigb in proportion to tbeir breadth and thickness. They manifest 

 this proportion, indeed, in a higher degree than do tbe teeth of 

 SpalacotJierium, and, being rounded or cylindroid at the aspect 

 exposed, have suggested to me the generic name Stylodon, signifying 

 '' pillar- tooth." Tbe 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 tbe fore part of tbe base rather more produced than the bind 

 part : the crown of the next tooth is somewhat longer : that of tbe 

 antepenultimate has a broader base, produced anteriorly into a minute 

 angle, and sbghtly thickened behind, but not developed into a con- 

 tinuous cingulum. Tbe apical half of tbe crown is broken off in tbe 

 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, like- 

 wise, severally smaller than tbe antepenultimate tooth. The seventh 

 tooth, coimting forward, is more abruptly smaller than tbe rest, with 

 a simple conical crown, indicating only a feeble prominence of the 

 fore part of tbe base. Then rises the crown of the largest tooth of 

 the series, laniaiiform, subrecurved, or seeming to be so, from the 

 convexity of the front border, and the minor concavity of the bind 

 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 natui'e of tbe above described eight 

 teetb, in tbe absence of information as to tbeir relations to deciduous 

 teeth, must be made on unsatisfactory and uncertain grounds. 

 Guided by their shape and proportions, we might view tbe foremost 

 as a " canine," the next four as " pre-molars," the last three as " true 

 molars," and thus infer an example of placental dipbyodont dentition. 

 Tbe objection to the two-fanged character of tbe canine would be 

 met by the same mode of implantation of the canine of tbe common 

 mole (Taljpa), the proportion of which tooth to the succeeding pre- 

 molar is very similar to that presented by Stylodon. 



But the proportion of tbe preserved dentigerous part of the present 

 fossil to the part behind indicates a greater number and size of 

 teetb in advance of the laniariform tooth than the three small 

 incisors of Talpa. Tbe closer similarity of tbe narrow columnar 

 binder molars to those in the Cape mole (GlirysocMoris, Cuv.), and 

 the very probable addition of an eighth such molar to tbe seven in 

 place behind tbe laniariform tooth of the fossil, warn us of the dece23tive 

 character of the analogy of tbe dentition of the common mole. It is 



