Suggests man’s original mode of walking and running is similar to that of quadrupeds.

He also suggests CD answer critics who say no new species has ever been unequivocally traced to its origins, by pointing out that there is no unequivocal account of the origin of surnames.

Thanks HBD for his note. The analogy of surnames had not occurred to CD – only that of language generally, as shown so well by Lyell. Fears HBD’s argument about progression would not have much weight.