In order to shed some light on the origin of this peculiar crossed polydactyly, the male parent of the 13 abnormal fetuses was used again for additional matings with control females
Among the 5 females showing a vaginal plug, one revealed to be not-pregnant on day 18, another gave 11 fetuses without any polydactyly and the three remaining females gave each a low proportion of fetuses with postaxial polydactyly in the forelimbs (2/15, 3/12 and 1/11, respectively) and no preaxial polydactyly.