. The structure and life of birds . Fig. 9.—Skull of bird (Rhea) viewed from below,c, condyle ; , entrance of spinal cord. (2) The lower jaw articulates with a bone calledthe Quadrate, which may be easily recognised. Itroughly resembles a St. Andrews cross. To the twolower and shorter arms the lower jaw is hinged. Tothe outside corner of the outer of these is attached along thin bone, which connects with the upper outer of the two upper arms fits into a hollowin the bone called the Squamosal. In mammals thequadrate is represented by an insignificant bone, theAnnulus of the ear (fig
. The structure and life of birds . Fig. 9.—Skull of bird (Rhea) viewed from below,c, condyle ; , entrance of spinal cord. (2) The lower jaw articulates with a bone calledthe Quadrate, which may be easily recognised. Itroughly resembles a St. Andrews cross. To the twolower and shorter arms the lower jaw is hinged. Tothe outside corner of the outer of these is attached along thin bone, which connects with the upper outer of the two upper arms fits into a hollowin the bone called the Squamosal. In mammals thequadrate is represented by an insignificant bone, theAnnulus of the ear (fig. 10, see p. 135). (3) In mammals the centra, the strong bases fromwhich spring the arches of the vertebrae, have betweenthem plates of bone, called Epiphyses, which are Ill RELATIONSHIP TO REPTILES easily distinguishable. These are absent both inbirds and reptiles (fig. ii).. Fig. io.—Side view of head of Rhea. Q, quadrate ; QJ, quadrato-jugal, hindmost component of bone connecting with upper jaw ; SQ, squamosal. (4) The coracoid bone is present. In man there isonly a small remnant of its upper end. It is well
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1895
