The articulation of the mandible to the quadrate-bone is such as to allow of a very considerable amount of lateral play, and, by a particular arrangement of the muscles which move the former, it comes to pass that so soon as the bird opens its mouth the point of the mandible is brought immediately opposite to that of the maxilla (which itself is movable vertically), instead of crossing or overlapping it - the usual position when the mouth is closed.
It may assume the form of a bivalve shell entirely enclosing the body and limbs, as in many 6, maxilla (second maxilla).
In generalized biting insects, such as cockroaches and locusts (Orthoptera), the parts of a typical maxilla can be easily recognized in the labium.
Watson has shown, is hardly distinguishable; (2) Eudyptes, in which the bill is much shorter and rather broad; and (3) Spheniscus, in which the shortish bill is compressed and the maxilla ends in a conspicuous hook.
The Dermaptera and the Orthoptera agree in having welldeveloped mandibles, so that the jaws are adapted for biting; in the incomplete fusion of the second maxillae (which form the labium) so that the parts of a typical maxilla can be easily made out (see the description and figures of the cockroach' g.
Solid as it looks, its weight is inconsiderable, and the perfect hinge by which the maxilla is articulated adds to its efficiency as an instrument of prehension.
The most obvious feature the Apteryges afford is the presence of a back toe, while the extremely aborted condition of the wings, the position of the nostrils - almost at the tip of the maxilla - and the absence of an after-shaft in the feathers, are characters nearly as manifest, and others not less determinative, though more recondite, will be found on examination.
The poison-bag lies on the side of the head between the eye and the mandibular joint and is held in position by strong ligaments which are attached to this joint and to the maxilla so that the act of opening the jaws and concomitant erection of the fangs automatically squeezes the poison out of the glands.