Abstract:
After giving a description of two instances of cervical ribs in bovines, these cases are considered in the light of various theories that have been advanced in explanation of such anomalies. It is concluded that both of them are covered by the atavistic or reversionary theory, which is here specifically defined as indicating that heredity has supplied the material from which, through stimulation probably emanating from the organism’s environment, there develops a structure resembling that which was normally present in an evolutionary ancestor.
