BISHOPINO. '763 



become parrot-mouthed in their old age. Surgical interference is 

 generally required in well-developed cases of parrot-mouth ; 

 because this condition greatly diminishes the animal's power of 

 seizing and cutting his food with his front teeth. 



It is not a very rare occurrence to find the lower jaw slightly in 

 advance of the upper one, which is a peculiarity that renders the 

 animal " under-hung '' (pre-normal occlusion of dentists). I have 

 seen this condition in a horse, and also in a mule, existing to such 

 an extent that the lower front incisors almost completely hid from 

 view the upper front incisors. The posterior aspect of the lowet 

 incisors was a good deal worn away by friction with the anterior 

 face of the upper incisors. 



Irregularities in the Teeth. 



We sometimes find one or more supernimierary permanent 

 incisor teeth (Figs. 210, 211, 212, and 213, pp. 766-768), especially 

 in the upper jaw. These teeth form a more or less complete row 

 behind the ordinary incisors. They are entirely different from the , 

 stumps of milk teeth which are sometimes retained (Fig. 214, p. 

 769) ; are inserted more or less firmly in the jaw ; and interfere 

 to a greater or less degree with the regularity of the respective 

 positions taken up in the jaw by the ordinary incisors. 



In rare cases, the incisors assume irregular forms even in young 

 mouths. 



The presence of a supernumerary molar is very rare in a horse. 

 Fig. 215 (p. 770) shows this peculiarity on the near side of the 

 lower jaw of a ten-year-old animal. As it could not be a case of 

 atavism (reversion to a m.ore or less remote ancestor), it was 

 probably one of dichotomy (splitting into two parts). 



The irregularities due to crib-biting have been alluded to on 

 page 554. 



Bishoping 



is a fraudulent operation, which consists in giving a false 

 appearance of youth to the incisors of an old horse (Fig. 216, 

 p. 7-71) by shortening the length of two or more of them aiid 

 making cavities in them to resemble " marks." Tlie trick can be 

 easily seen by the absence of enamel round- the false " marks ; '' 

 by the spaces between the upper and lower incisors, when the 

 jaws are brought together (Fig. 217); by the shape of the tables; 

 by the shape of the teeth ; by the narrowness of the neck of the 

 teeth ; and by the marks of the file. 



