158 



C. R. BARNICOAT 



Fig. 1. Central incisors from 18-month-oId (two-tooth) ewes (x 3). The 

 gum level is shown by grass stain (arrows) in A and C. The junction of enamel- 

 covered crown and root is marked with pencil, and the unerupted part of the 

 crown lies between arrow and pencil mark. A contained approximately twice 

 as much "useful tooth substance" as C; B, a wide tooth, though rather less in 

 weight than A, is a better type of tooth. 



sheep taken at intervals until they attained the age of 5 to 6 years 

 did other well defined faults become evident. They are: narrow 

 teeth, "splayed" or "fanned" central incisors, overlapping central 

 incisors, deep "V" in central incisors, and cleft palate. 



All these abnormalities are also detrimental to the lasting quality 

 of the teeth, and it is unusual to find only one type of fault present 

 in a defective mouth. Moreover, certain defects in 5-year-old mouths 

 are totally different in appearance at the early stages; for example. 



