| OCR Text |
Show 546 ON THE ANATOMY OF .ECHMOPHORUS MAJOR. [Apr. 2] and to the Plovers being only seen in one species of each group and in the aberrant Rhynchops. There is, moreover, the same amount of likenesstotheLimicolae proper in a small point which may be regarded as of equal importance. The biceps slip, always present in theAlcids has, at least as a rule, rather unusual relations. Thus in Alca torda Fiirbringer figures it as attached partly to the patagial membrane and partly to the inner of the two brevis tendons. In the Gull the insertion is the more normal one, i. e. on to the longus tendon. In Fratercula arctica the muscle is inserted upon the middle of the three brevis tendons. N o w in a specimen of Trinya canutus (doubtless individual variation), I found a second biceps slip in addition to the usual one, which was inserted on to the outer of the two brevis tendons. This tendon I take, for reasons already explained, to correspond to the middle of the three tendons of Fratercula. I have carefully studied the wdndpipe of a number of Auks, and can find no reasons for associating them especially with the Gulls from an examination of this organ. The syrinx is seen in its most characteristic, even exaggerated, form in Ceratorhina monocerata. In this A u k (fig. 6) the first bronchial semiring is the shape of half an ellipse-a gross exaggeration of the generally arched form of this ring in the avian syrinx; the same form is shown by the second bronchial semiring, which lies as it were inside the first Fig. 6. Fig. 7. Fig. 6.- Syrinx of Ceratorhina monocerata : i, intrinsic muscles. Fig. 7.-Syrinx of Lomvia troile: i, intrinsic muscles. and is concentric with it. The intrinsic muscles are attached to the first. Nothing of this kind occurs in any Gull or Limicoline bird known to me. In other Auks, however (fig. 7), the syrinx is decidedly more typical in form. It is an interesting fact that w e can arrange the family into two subfamilies according to |
