St.) is directed downwards and tapers out into a thin, partly cartilaginous, strand, which originally extended to the inner corner of the articular portion of the mandible, but on its long way comes to grief, being squeezed in between the pterygoid and quadrate.
Tracheae typically opening by stigmata situated in the articular sockets (acetabula) of the 3rd, 4th, 5th and 6th pairs of appendages.
G, prefrontal; M, maxilla; J, poison-fang; Tr, transpalatine; Pt, pterygoid; p, palatine; Q, quadrate; Sq, squamosal; Pm, premaxilla; T.a, articular; Pe and Di, muscles.
Dentary movably attached to the tip of the articular bone of the mandible.
Asia and Central America is remarkable for having the dentary bones loosely attached to the apex of the elongated articular bone.
Lower articular surface of the astragalus divided into two nearly equal facets, one for the navicular and a second for the cuboid bone.
The calcaneum with an articular facet for the lower end of the fibula.
I, C) and with their articular surfaces for the toes smooth, instead of ridged as in the Pecora.
Many of them, like ungulates, are specialized for swift running, and have unusually long limbs, with ridges developed on the articular surfaces of the lower bones; the clavicles are more or less reduced; the thorax is more compressed than usual, with a narrower breast-bone; and there is a marked tendency to the reduction or loss of the lateral toes, more especially in the hind limb.
Their lower articular surfaces, instead of being pulley-like, with deep ridges and grooves, as in other Artiodactyla, are simple, rounded and smooth.
Three series are distinguished, podobranchiae, attached to the proximal segments of the appendages, pleurobranchiae, springing from the body-wall, and an intermediate series, arthrobranchiae, inserted on the articular membrane of the joint between the limb and the body.
This twisting is in a great measure owing to the manner in which the bones of the wing are twisted upon themselves, and the spiral nature of their articular surfaces - the long axes of the joints always intersecting each other b FIG.
- Ambulacral pairs fused to form vertebrae with definite articular surfaces; mouth, radial and genital shields developed, though not all need be present in any one form.