318 STRUCTURE AND CLASSIFICATION OF BIRDS 



be exchanged for that of " pigeon grouse." There is, in my 

 opinion, much to be said for this view, which, however, is 

 not now so generally held. HUXLEY'S view was based 

 almost exclusively upon osteological characters, with but 

 slight reference to the anatomy of the soft parts, which were 

 indeed when he wrote (in 1868) scarcely known. The 

 several regions of the vertebral column in the sand grouse 

 have the same number of vertebrae as in the ' Alectoromor- 

 pha?,' ' and ankylosis takes place in the same manner.' The 

 skull is dove-like for the most part ; but in. certain ways it 

 approaches the Galli. For instance, the maxillo-palatines are 

 alike in both groups of birds ; the union between the squa- 

 mosal and the post-frontal process is gallinaceous ; the 

 holorhinal nostrils, which I must term those of Pt erodes, 

 indicate a likeness to all the members of the group Galli. 

 The remainder of the skeleton is, in HUXLEY'S opinion, 

 ' peristeromorphous,' but the pelvis is partly grouse-like. 

 Attention may be directed to the likeness of the sand 

 grouse humerus to that of pigeons. The osteological cha- 

 racters, however, are not quite so intermediate in some 

 respects as might be inferred from HUXLEY'S paper. The 

 at least ' pseudo-holorhinal ' nostrils have their counterpart 

 among the Limicolse, in Thinocorus, and in some others (see 

 below). The solid ectethinoids too are also seen in that 

 group, while GAEEOD'S remark that the Alcae have a hu- 

 merus like that of Columbae and Pterocles is suggestive in the 

 light of the unquestionable likeness of the Alcae for the Limi- 

 colae, though the actual weight of this character may be 

 thought by some to be discounted by the fact that it is met 

 with in the Psittaci. 



Moreover Otis, which is to be placed somewhere near the 

 Limicolse, has the gallinaceous union between the squamosal 

 and the post-frontal process, to which I have referred as 

 possibly affining the Pterocletes to the Galli. Other characters 

 too, which appear at first sight to be arguments in favour of 

 the position taken up by HUXLEY, may be interpreted fairly 

 as marks of affinity with the Limicolse (and their immediate 

 allies). Such are, for example, the long ca?ca (with folds in 



