292 



On a new Tijpz of RtptiUan, Tojlh. 



external wall of dentine is now seen to thicken at the expense 

 of the pulp-cavity, which has lost its five-raye.l form and 

 become more L-shaped. The inn^r wall of the canal E 

 appears to be broken, but the inner walls of the other canals 

 have thickened, especially on the external side of the tooth 

 (rt^'. 2). 



The distal fracture of the tooth is much more recent and 

 shows the pulp-cavity reduced to a curved hamate form 

 situate towards the inner side of the tooth and only two tenths 

 of an inch wide in the middle. The inlet E is imperfectly 

 separated from the pulp-cavity, ]irobably from the effect of 

 strain, though the partition of dentine between them remains 

 as thin as in the basal section (fig. 1). The inlet D retains 

 its comma- or flask-shaped form without decrease in sizi. 

 The inlets C and B are almost entirely closed by the approxi- 

 mation of the lateral external walls (fig. 3). The tooth- 

 substance in which they are contained is tuUy half an inch 

 thick, but on the inner side of the tooth the walls of dentine 

 are only from one to two tenths of an inch thick. 



Fin;. 3. 



Distal fracture of the tooth. 



These inlets have been regarded by Dr. Kannemeyer as 

 comparable to the poison-duct in the tooth of a venomous 

 serpent. The inlet D is essentially of this character, and 

 althouf^h the entire tooth is to be desired before the inference 

 can be regarded as established, it is not improbable that all 

 the canals may be outlets for poison-glands. 



Externally the five bars of the tooth are vertically ribbed 

 with six to ten slightly elevated, blunt, parallel, linear stripes, 

 which are stronger on the outer than on the inner side. 

 There is a very slightly elevated girdling ridge, situate below 



