478 Mr. I*. H.jjowe on the Significance of certain [Ibis, 



Such reflections give pause foi* thought, and we liave to 

 seriously ask ourselves if the origin of characters such as 

 colour-pattern (or indeed any characters) can be explained 

 hy a blind appeal to the old formulas. 



To turn, however, from speculation, we find that although 

 a single and striking form of colour-pattern (too well known 

 to require noting here) is characteristic of the " Golden 

 Plover group " regarded as a whole, this group in reality 

 consists of two subgroups which have been distinguished by 

 generic rank ; that is to say, the Grey Ployer has been 

 relegated to the genus Sijuatarola and the Golden Plover 

 to the genus Pluvialis. 



The only reason which has been atlvanced by systematists 

 for the recognition of the genus Squatarola is, so far as I 

 am aware, the presence of a rudimentary hind-toe ; while 

 the author of the anatomical notes in ' The British Bird 

 Book ' has definitely stated in a footnote on page 573 that 

 it is impossible to recognise such a genus at all. In reality, 

 some rather remarkable anatomical characters, apparently 

 hitherto overlooked, seem to fully justify the generic 

 separation of the Grey from the Golden Plover. I am not 

 immediately concerned, however, with ihe justification of 

 either one or the other genus, but rather with the problem 

 of the significance of the somewhat remarkable deep-seated 

 differences which characterise the two groups. 



These differences may be described as follows : — 



In the first place, only two cervico-dorsal vertebrre with 

 two free ribs are present in Squatarola, while in Pluvialis 

 there are three. Here, at once, we find a meristic pheno- 

 menon which is difficult to explain by any appeal to the 

 influence of either function or environment. 



Turning to the skull we find : — 



(a) That the lacrymals in Squatarola are strikingly dif- 

 ferent, being prominent out-jutting processes, almost Larine 

 or Tringino in appearance ; while in Phmalis their outer 

 margin is rounded and merged into the line of the orbital 



