1922.] (/haractfrs in some Charadriine (jevem. 487 



funcif all}') compared to iiii artist's rough study or preliminary- 

 sketch, of the more firmly painted-in colour-pattern charac- 

 teristic of the ('ommon Kinged Plover grou[) ((/. Plate YI. 

 figs. 4-G). 



These adumbrations or "studies'^ of colour-pattern I lun'e 

 often observed in other groups or phyla throughout the whole 

 class of birds. To my fancy they have appeared to be "first 

 attempts" on the |)art of Nature to produce the more com- 

 pleted sketch; and I think that there is oround for reoardin"- 

 the species of any group with these "adumbrated studies" 

 of colour-pattern as being earlier in point of time of origin 

 than those with more definitely completed colour-patterns. 

 Moreover, such adumbrations of colour-pattern may be found 

 in one part of the area of distribution of a group of species, 

 while the more complete sketch may be found in another. 



It will doubtless be answered that these faintly outlined 

 "studies'" are merely the result of environment caused, 

 for example, by excess of light and aridity, or what not, 

 in more barren or desert surroundings ; but it might, I think, 

 be ju.>t as reasonably argued that if a group or phylum of 

 species belonging to an earlier geologic horizon and charac- 

 terised by such a faintly marked colour-pattern sketch did 

 not unconsciously seek an environment adapted to suit its 

 case, it would be less likely to survive. In the case of the 

 Kentish Plover group this presumably has been done in 

 Europe, America, and Australia, and as a consequence they 

 have survived. 



But, it may be said, if we have a Squatarola-PluviaUs and 

 a LeucopoUiis-Charadruis group, each composed of sub- 

 groups representative on the one hand of a more recent 

 and on the other of an earli(u- geological horizon, the earlier 

 forms {Squatarola and Leucopolius) must be regarded as 

 virtual " living fossils/^ and this, I think, we may take for 

 granted ; for of all classes Birds are the most amazingly 

 persistent. In the case of Mammals, forms cliaracteristic of 

 past geologic horizons are for the most part extinct and 

 fossilized. In the case of Birds it is open to doubt if we 

 ornithologists suificioutlv reflect what a number of livin"- 



