Though few authorities include Amblypoda in modern classifications, scientists once defined it as a group of extinct, herbivorous mammals common to North America during the Tertiary period. Once considered a suborder of primitive ungulates, or hoofed mammals, experts have since concluded that members do not share a common ancestor. They do agree, however, that the group’s members had very small brain cavities relative to their mass. From what physical characteristic is the group’s name derived? Discuss
Source: The Free Dictionary