484 Mr, P. R. Lowe on the Significance of certain [Ibis, 



kuown to need descri[)tion here but thoroughly charac- 

 teristic of: the " Ringed Plovers,'^ although in Leiicopolius 

 the colour-pattern is, so to speak, adumbrated — a point to be 

 further noted {cf. Plate VI.) 



As regards osteological features, we find a similar state 

 of affairs as we did in the " Golden-Plover Association " ; 

 that is to say, the skulls of all the species of Leiicopolivs 

 examined * present features exactly reminiscent, if not iden- 

 tical, with Squatarola^ while those of CJiaradrnvs resemble 

 Pluvialis {cf. figures). 



This is all the more remarkable when we consider the very 

 great distances which separate the various species in either 

 group. Thus in Leucopolius we find L. ale.vandrinus breeding 

 in Europe and Asia, L. nivosus in America, and L. mtficapil- 

 his in Australia ; while as regards Charadrius we find in the 

 case of C. hiaticula (Europe and America), C. placidus (China 

 and Japan), C. semipalmahis (America), and C. monaclms 

 (Australia) equally astonishing distances separating the 

 various forms. 



In the case of the colour-pattern characteristic of the 

 downy nestlings of the two groups, there is not only a quite 

 obvious generic difference, but in each of the two genera 

 there is an equally striking similarity between individual 

 species no matter what the distance may be separating them ; 

 for instance, the coloration and the colour-pattern of the 

 downy nestlings of L. alexandriniia (Europe), L. nivosus 

 (America), and L. rnficapilhis (Australia) are so precisely 

 identical that, if the nestlings were inadvertently mixed, it 

 would be all but, if not actually, impossible to separate them, 

 and the same applies to the genus Charadrius {cf. PI. VI.) 



* * * * * 



Such, then, are the series of characters which we may 

 observe to differentiate either of the two subgroups or genera 

 into which the " Golden-Plover " and the " Ringed-Plover " 

 associations may be divided — subgroups, it may again be 

 noted, which in each case are obviously linked by phylo- 

 genetic characters, such as colour-pattern and anatomical 



* See further on, p. 489. 



