348 STRUCTURE AND CLASSIFICATION OF BIRDS 



formed by the union of the lacrymal with a process of the 

 frontal, forming a continuous bony bar. As has been already 

 mentioned, (Edicnemus shows a very considerable approach to 

 this state of affairs. So too, as I interpret it, do the quite 

 typical charadriid Vanellus and Eudromias. In these birds 

 the grooves for the supra-orbital glands do not, as they 

 do in Limosa and Recurvirostra, border the margin of the 

 orbit. They are situated at some distance from it, and each 

 ends in a very small foramen, bordered in front by the 

 ankylosed lacrymal, which I take to correspond to the large 

 foramen of Chionis. 



There are 110 occipital foramina or basipterygoid pro- 

 cesses. 



The cervical vertebra are fifteen, of which the last three 

 bear discrete ribs ; six ribs reach the two-notched sternum, 

 and there is one behind. The clavicles have no hypocleidium, 

 and end a long way in front of carina. The coracoids are 

 not in contact at sternal articulation. 

 The muscle formula is ABXY+. 



The syrinx of Chionis is not widely different from that 

 of other Limicolse, and exhibits, as will be seen from the fol- 

 lowing description, no particular resemblance to the Galli. As 

 is the case in so many Limicolae, the intrinsic muscles end as 

 such some way in front of the bifurcation of the windpipe, 

 though they are continued on to the bronchi by fibrous tissue. 

 They end in Chionis upon the fifth tracheal ring counting 

 from the last. 



The last four tracheal rings are more or less closely united 

 to form an ossified box. The first bronchial semi-ring to 

 which the fibrous continuation of the intrinsic muscles is 

 attached is the widest (from before backwards) of the rings 

 of the windpipe, and is deeper than the bronchial semi-rings 

 which follow. 1 



1 The following are the principal memoirs dealing with the anatomy of this 

 bird : EYTON, ' Note on the Skeleton of the Sheathbill,' P. Z. S. 1858, p. 99 ; 

 A. REICHENOW, ' Osteologie von Chionis minor,' Ac., J. f. O. xxiv. 1876, p. 84 ; 

 SHUFELDT, ' The Chionidse : a Review of the Opinions on the Syctematic 

 Position of the Family,' Auk, 1893, p. 158, and in ' Contributions to Comparative 

 Osteology,' &c., J. Anat. 1'lii/s. 1891, p. 509 ; KIDDEK and COUES, ' A Study of 



