Male with an intromittent copulatory organ.
The intromittent organs of the male are remarkable for their complexity and elaboration.
When adult the males may always be distinguished from the females by the presence of a pair of horny intromittent organs, one of which is lodged in the terminal segment of each palpus or appendage of the second pair.
The name given to this small but remarkable group has reference to the position of the male intromittent organ (fig.
The terminal part of the male ducts may be protrusible and act as an intromittent organ, or this function may be discharged by some of the appendages, as, for instance, in the Brachyura.
Between them is situated, sometimes asymmetrically, the prominent intromittent organ.
The penis is the intromittent organ of generation, and is made up of three cylinders of erectile tissue, covered by skin and subcutaneous tissue without fat.
The fourth category is represented by the Apoda or Caecilians in which, as we have stated above, the male is provided with an intromittent organ.