The male then mounts the back of the female, and both animals rotate their tails so that the respective cloacae are brought into contact and intromission of the male erectile organ is achieved.
Finally he mounted her and began to achieve intromission.
Oakland eventually achieved intromission while Baez remained motionless, then he lowered his chin to her shoulders, and even groomed her back with his tongue.
Among the tuatara's unusual reptilian traits are the relatively simple structure of its heart and lungs, the somewhat froggy style of its gait and the absence of any sort of male intromission organ, or penis.
Even though the female's organ is flaccid during copulation, its only opening points forward and downward, so the male must hop around behind the female while he squats behind her, thrusting blindly upward and backward, to achieve intromission.
Kit Opie who ran the study with Matilda Brindle at University College London, said that penis bone length was longer in males that engaged in what he called "prolonged intromission".
The penis bone, which attaches at the tip of the penis rather than the base, provides structural support for male animals that engage in prolonged intromission.
Avicenna's depiction of the five external faculties of the soul follows Aristotle's De anima, the senses receiving the impressions of their designated sensible objects by intromission.
Bacon is committed to an intromission theory of vision, though he combines it with an extramissionist theory that avoids the anthropomorphisms of earlier extramissionist theories.
His integrated optics model follows an Epicurean and Lucretian intromission view, that vision is a function of rays of light atoms or image-bearing atoms that are received by our internal apparatus for vision.
For this tradition, vision occurs when the crystalline humor is altered by the intromission of visual species from the object.
