It thus formed a tail of the size of the nail of the little finger, with a length of nearly 3/16 inch on the inner surface and 3/8 inch on the rear surface.

This little tip could be raised from the body and it slowly sank back.
In addition to the familiar caudal projection of the human fetus, Dickinson mentions a group of other vestigial remains of a former state of things.

Briefly these are:-- (1) The plica semilunaris as a vestige of the nictitating membrane of certain birds.
(2) The pointed ear, or the turned-down tip of the ears of many men.
(3) The atrophied muscles, such as those that move the ear, that are well developed in certain people, or that shift the scalp, resembling the action of a horse in ridding itself of flies.
(4) The supracondyloid foremen of the humerus.
(5) The vermiform appendix.
(6) The location and direction of the hair on the trunk and limbs.
(7) The dwindling wisdom-teeth.
(8) The feet of the fetus strongly deflected inward, as in the apes, and persisting in the early months of life, together with great mobility and a distinct projection of the great toe at an angle from the side of the foot.
(9) The remarkable grasping power of the hand at birth and for a few weeks thereafter, that permits young babies to suspend their whole weight on a cane for a period varying from half a minute to two minutes.
Horrocks ascribes to these anal tags a pathologic importance.

He claims that they may be productive of fistula in ano, superficial ulcerations, fecal concretions, fissure in ano, and that they may hypertrophy and set up tenesmus and other troubles.

The presence of human tails has given rise to discussion between friends and opponents of the Darwinian theory.