Modus operandi among male inverts is, in the first place, stuprum mutuum. The other frequent method is thigh friction, “membrum fricando inter femora cynedis qui jacet in tergo, mulieris instar.” Another quite frequent mode is insertio fascini in os. In the majority of cases paederastia consists in initus per anum. Juvenal when speaking of the “condylomes in cynedes” says: “Sed podice laevi caeduntur tumidae, medico ridente, mariscae.” “Nates sunt semper repulsae cum manibus.” Modus operandi among homosexual female inverts is, apart from stuprum mutuum, threefold. In the majority of cases it consists of tribadism (from the Greek word τρίβειν, to rub), namely in a simple contact and “fricatio genitalium unius versus genitalia alterius,” or as in Moll’s case, “ut una premeret femur alterius.” The second mode is cunnilingus and fellatricia, which consists in “lambere lingua genitalia alterius” and in “fellare clitoridem et labia minora alterius.” The third mode is clitorism, which is only possible when the clitoris is abnormally long, so, as Martial says, “Inter se geminos audent committere cunnos “Mentiturque virum, prodigiosa Venus.” In such cases commixtio consists in the “introductio auctae clitoridis in vaginam alterius.” Such cases with enlarged clitoris are not so very rare even in normal women. A few years ago the author performed a total vaginal extirpation on a sexually normal woman whose clitoris in non-erect state measured three and a half centimeters. A woman masturbator is known to the author whose clitoris, when erect, measures three centimeters. Kiernan reports a case in which a sexual invert possessed a clitoris which, when erect, measured six and a half centimeters, or two and a half inches. _Psychical Hermaphrodism._—The homosexual perversion shows four degrees. In the first degree traces of heterosexual feeling are yet to be found, but the homosexual instinct predominates. The characteristic of the so-called psychical hermaphrodism is the pronounced sexual inclination toward the same sex besides the periodically present desire for the opposite sex. The homosexual feeling is of great intensity and permanent, while the intensity of the heterosexual inclination is of a much lesser degree, and the feeling is only present at certain times. A young man, thirty-two years of age, was seduced by a boy of fourteen to stuprum mutuum when he was only eight years old. In his lascivious dreams he sees only men. When eighteen years old he fell in love with a beautiful young girl. Initus with her, although successful, did not afford him the libido he had expected and he stopped having carnal relations with her. On the other hand, the pleasure experienced in his relations with men is of great intensity.