Table 1.

Differences in total coccygeal vertebrae based on genetic background

	Age (d)
Strain	3	21	42
129	16	26	27
BALB/c	21	27	28
B6	15	26	27
C3H	18	25	28
FVB	16	27	28
SW	18	27	29

Values represent the mean vertebral number from 6 mice at each age using microRad.