The Crural Plexus is divided into a crural, ischiadic and pubic portion.
The first is generally composed of three nerves, the hindmost of which, the furcalis, issues in most birds between the last two lumbo-sacral vertebrae, and then divides, one half going to the crural, the other to the sciatic portions.
The cardinal process is prominent, and on each side of the hinge-plate are situated the dental sockets; the loop in Terebratulina becomes annular in the adult by the union of its crural processes (fig.
The name " coxal gland " needs to be carefully distinguished from " crural gland," with which it is apt to be confused.
The crural glands, which occur in many terrestrial Arthropods, are epidermal in origin and totally distinct from the coxal glands.