40 



Proceedings of the Boyal Physical Society. 



rally led to examine with care the roof of the mouth in the 

 Dunbar specimen. The palatal mucous membrane was not 

 uniform in appearance. In the anterior third it was studded 

 generally with very short papilke — so short, indeed, that they 

 would probably have been overlooked if my attention had 

 not been directed specially to them. In the middle and 

 posterior two-thirds the palatal mucous membrane was quite 

 smooth in the centre of the palate ; but on each side, up to 

 the groove that marked the junction of the palate and 

 upper lip, it was studded with multitudes of short papilke, 

 some of which were sharp, others truncated, and which were 

 so stunted as to be very slightly elevated above the general 

 plane of the mucous membrane. 



I shall now pass to the consideration of the dentition of 

 Hyjjeroodon, and shall describe what I have seen in connec- 

 tion with both the lower and upper 

 jaws; and in working out the dissection 

 which was required I have been aided 

 by my museum assistant, Mr James 

 Simpson. When the gum was removed 

 from the tip of the lower jaw, the points 

 of a pair of mandibular teeth were ex- 

 posed about half an inch from the sur- 

 face. The crowns of these teeth were 

 about half an inch long, and the fangs 

 were imbedded in the mandible. On 

 shaving off thin slices of the gum, for 

 about three inches behind each man- 

 dibular tooth, the sacs of seven rudi- 

 mentary denticles were exposed in the 

 substance of the gum. Each sac, with 

 a single exception, was not larger than 

 would contain a big shot, and each con- 

 tained a soft uncalcified or partially 

 calcified denticle representing the crown 

 of a tooth. These sacs were separated 

 to show the tooth pulps from each other by intervals of not more 



anri acrna 'I'hic; nun ttiA u 



than half an inch. Behind the last of 

 these sacs, up to the posterior end of the 



Fig. -d. 

 Gum of a portion of 

 one side of the lower jaw 

 behind the mandibular 

 tooth. The surface of the 

 gum has been shaved off 



and sacs. This and the 

 succeeding figure have 

 been drawn by my son, 

 Mr \V. A. Turner. 



