100 



SOUNDNESS IN HOESES. 



Irregularities in the form of the incisor teeth. — In some 

 rare cases, " the incisors of the lower jaw have a well- 

 marked triangular form, nearly the same as may be 

 observed at the age of fourteen or fifteen. The presence 

 of the central enamel in all the lower incisors, will 

 guard us from being deceived by this extraordinary 

 triangularity of shape " {M. Girard). 



^ / 



Fig. 23. 



Fig. 23 shows a double upper middle incisor united in 

 such a manner as to give the appearance of a single 

 tooth. The size of the tooth, the existence of a longi- 

 tudinal ridge that marks the line of union, and the 

 presence of two complete and separate dental cavities, 

 show that it is double. 



In Fig. 24, as is not very uncommon, some of the 

 incisors are fissured. 



