IRREGULARITIES OF THE DENTAL APPARATUS. 729 



corners than on the intermediates, and on the latter than on the pincers. The 

 teeth which are normally constructed will always act as landmarks in determining 

 the wear. 



/?. Duplication. — A much less frequent malformation is the duplication or 

 doubling of the infundibula formed by the central enamel, resulting, consequently, 

 in the presence of two external dental cavities upon the same surface of friction 

 (Fig. 316). This fact, which we have pointed out for the first time,* and of which 

 we possess some examples, has no impoi'tance as regards the determination of 

 the age. These anomalies must not be confounded with those of fusion or solder- 

 ing of two teeth, of which we have spoken ; for, in the former case, the teeth 

 are no larger than when in a normal state, and show, besides, no external trace 

 of a previous fusion. It is probable that this anatomical disposition is the result 

 of the bifurcation of the external papilla, or germ of enamel. In certain sub- 

 jects, one of these two cavities is cleft behind and opens upon the posterior face 

 of the tooth, instead of being entirely isolated, like the other one, upon the central 

 part of the dental table. 



5. Irregularities in the Depth of the Infundibulum and its 



External Dental Cavity. 



a. Beguite. — When the external dental cavity or dental cup per- 

 sists upon the dental table at a period when it should have disappeared, 

 the animal is called begu, and does not mark his teeth properly, which 

 is designated beguite. (Plate XXXII.) 



We know already that the bottom of the infundibulum is filled by 

 a deposit of cement whose thickness can modify the depth of the 

 external cavity of the tooth. Besides, the eruption of the incisors 

 having taken place successively in pairs, from the pincers to the cor- 

 ners, the successive disappearance of these cavities is effected first upon 

 the teeth which complete their eruption first, and which, for this 

 reason, have been used the longer. It is this which constitutes regular 

 levelling. 



But this levelling can only take place in its normal siiccession, and 

 with such regularity, on condition that the external dental cavity has 

 almost the same depth in all the incisor teeth ; or, in other words, that 

 the cementous deposit of the infundibulum takes place in a layer of 

 uniform thickness. But as this is far from being the case in many 

 instances, since in certain pincers the cementous nucleus is two centi- 

 metres in thickness, while in others it scarcely attains a few milli- 

 metres, it can be very easily understood that an infundibulum almost 

 void of cement means a tardy levelling, and that an infundibulum filled 

 with cement means an early levelling. 



1 Goubaux et Barrier, Archives v6t6rinaires, ann^e 1881 , p. 133. 



