The formation of bone and cartilage in the penis is quite rare.

Velpeau, Kauffmann, Lenhoseck, and Duploy are quoted by Jacobson as having seen this anomaly.

There is an excellent preparation in Vienna figured by Demarquay, but no description is given.

The Ephemerides and Paullini describe osseous penises.
The complete absence of the frenum and prepuce has been observed in animals but is very rare in man.

The incomplete or irregular development is more frequent, but most common is excessive development of the prepuce, constituting phimosis, when there is abnormal adherence with the glans.