1 0 0 0 OA タヌキの歯数異常
Deficiencies and surplus eruptions in the teeth of raccoon-dogs were examined using 340 specimens collected mainly from three localities in western Japan. Abnormalities in the dentition occurred in 26% of 308 perfect skulls. On the upper jaw, 9 examples of pm-1 deficiencies on both sides occurred, 8 on left side alone and 4 on right side alone among 317 specimens. There were no significant differences between the sexes, but differences did exist among localities. There were i-1, i-2, i-3, pm-2 and m-2 deficiencies, and i-surplus eruptions in some specimens. On the lower jaw, m-3 deficiencies occurred more frequently. Incidences of deficiencies on both sides, left and right side alone were 19, 19 and 15 respectively among 314 specimens. No significant difference was found between sexes and among localities. Other deficiencies were observed on i, pm-1, pm-2, pm-3 and pm-4. One surplus eruption occurred between c and pm-1. In one specimen, pm-4 duplications in the buccolingual direction were observed on both sides.