726 



THE EXTERIOR OF THE HORSE. 



tional to find these teeth altogether absent, as in the horse of which we have 

 spoken. 



3d. Molars. As to the molars, we have seen only two examples of this 

 anomaly in the superior jaw. 



2. Irregularities of Form. 



" In certain subjects," says Girard, 1 " the incisors of the superior jaw pre- 

 sent, at the age of six years, a well-marked triangular form, almost the same as 

 is observed at fourteen or fifteen years of age." This premature triangular form, 

 which we have often noticed, even at five years of age, cannot lead us into error, 

 on account of the presence of the central enamel in all the teeth which have this 

 form. 



3. Irregularities caused by the Union of Two Teeth. 



Isidore Geoffrey Saint-Hilaire 2 a long time ago mentioned this variety of 

 irregularities, which is without importance in determining the age, but which 



should be considered as very rare, and re- 

 sulting from the fusion of two neighboring 

 dental follicles. They consist in an inti- 

 mate fusion of two teeth, sometimes more or 

 less distinct, at other times entirely con- 

 founded. 



We possess a specimen of the latter 

 kind (Fig. 314); the superior intermediate 

 was double, which could be easily recog- 

 nized by its large volume, the presence of a 

 groove corresponding to the line of fusion, 

 and the existence of two perfectly-distinct 

 external dental cavities. 



Messrs. Chauveau and Arloing 3 have 

 observed, in the clinic of the Veterinary 

 School at Lyons, an ass in which the pincers 

 and the intermediates were soldered together 

 in the inferior jaw. The incisor teeth were 

 only four in number instead of six, the 

 irregularity existing on both the right and 

 left sides. 



M. Ch. Morot * has reported a very re- 

 markable case of this kind in a gelding six 

 years old. The double tooth was super- 

 numerary and situated in the inferior jaw, external to and behind the corner, 

 which it touched. The two pieces which composed it were seven centimetres in 

 length and separated for the greater part of their extent, save at the level of the 



FIG. 314. Union, at a, of two superior in- 

 cisors, one of which is supernumerary. 



1 Girard, loc. cit., p. 66. 



2 Isidore Geoffrey Saint-Hilaire, loc. cit, t. i. p. 546. 



3 Chauveau et Arloing, Anatomic compared des animaux domestiques, 4e e"d., p. 413. 



* Ch. Morot, Bulletin de la Socie~t6 centrale de medecine veterinaire, p. 140, in Recueil de 

 me'decine veterinaire, an ne'e 1888. 



