No such relationship can be inferred, however. These, as well as the caudal appendage, are nothing more than anomalous malformations not traceable to any imaginary ancestral state. Warkany reports that while most persons with caudal appendages showed normal general development, caudal appendages have been associated with such malformations as meningocele, spina bifida, chondrodystophy, cleft palate, hemangiomas, syndactyly, hypodactyly and heterotopic anus. If malformations may possibly be due to the expression of genes inherited from distant ancestors but long suppressed, one can think of interesting suggestions. For example, some human females are born with mammary glands under the armpits.
Some bats normally have their mammary glands in that region.
Some human females are born with mammary glands in the groin region. Mammary glands normally occur in the groin region of some whales. Mammary glands, as a matter of fact, have developed in humans in many places, including the back, arms, and legs. This paper in The New England Journal of Medicine thus represents simply another contribution to the mythology generated by the occurrence of malformations in the newborn. M, Bartels, Arch.