724 



THE EXTERIOR OF THE HORSE. 



Concerning our own experience, we have seen only one example in the ass 

 (Fig. 312). 



Fig. 312. — Double right inferior canine in the ass. 



Molars. — Supernumerary molars in the horse and the ass have been ob- 

 served for a long time by Lafosse,^ Girard,'' M. Thomas,* M. Chuchu,* M. Morot,* 

 and ourselves.^ 



They exist nearly always in the superior jaw, either in the axis of the nor- 

 mal arcade or on the external side ; in the latter case, they may produce wounds 

 of the cheeks, a fact which has been observed by M. Chuchu. 



In the inferior jaw they are considered very exceptional. M. Morot has, 

 notwithstanding, related the case of a mare which presented a superior right 

 supplementary molar, and, at the same time, two inferior, one right and one left. 



Until the present time, the only facts known relate to the presence of a 

 single supernumerary molar in each jaw ; this tooth is most often situated behind 

 the others, next to the sixth. 



[We have in our possession a skull obtained from a Clydesdale mare, which 

 has seven molars in each arcade. The first molar is evidently supernumerary, 

 and very probably the first one of the seven molars in each arcade of the skull 

 of the hipparion, — a reversion of an ancestral form ; in other words, it is an 

 excessive development of the wolf-tooth.'] 



It is not within our domain to speak of the irregularities of locality, of which 

 science has collected several examples, in which the supernumerary teeth were 

 situated in the zygomatic process, or at the base of the ear, projecting sometimes 

 into the interior of the cranial cavity. These are heterotopic facts whose study 

 pertains especially to teratology. 



> Lafosse, loc. cit , p. 32. 



* Girard, TraitS de I'&ge du cheval, 3e 6d., p. 35. 



' Thomas, Journal de m^decine vet6rinaire militaire, t. xiv., 1876-1877, p. 687. 



* Chuchu, Recueil de mMecine v6ti5rinaire, annee 1877, p. 637. 



' Ch. Morot, Bulletin de la Soci6te centrale de m^decine v6t^rinaire, p. 434, in Recueil de 

 m6decine v6tt'rinaire, 1888. 



6 Arm. GouVmux, loc. cit., p. 71. 



