NATURAL SELECTION 



237 



(1929), and he expressed doubt as to the survival value of the 

 pallor of the insular race, as the latter is nocturnal. More- 

 over, (a) the lack of enemies, (b) the fact that the white race 

 lives not on the light sand but in the scrub of the island, and 

 (c) the discovery that the light race lives on dark soil on an 

 adjacent spit, all tend to weaken the case as Sumner originally 

 presented it. 



Sumner (1932, p. 69 and foil.) discussed this case in the 

 light of further knowledge, and seems to waver as to the pro- 

 tective coloration explanation. He admits (I.e.) that one is 

 almost driven to accept the latter explanation through lack 

 of any other adequate explanation ; but he is evidently keenly 

 alive to the difficulties inherent in the proposition. Thus he 



FLORIDA,,-^ 



QULF Of MEXICO 



Fig. 22. — Map showing Localities in which Peromyscus polionotus albifrons and 



P. p. leucocephalus were trapped by Sumner. 



(From Sumner, 1928.) 



cites his own observations on a colony of albifrons which lives 

 on a similar isolated white beach but which does not show the 

 same colour condition as leucocephalus ; and he is at pains to 

 point out that depigmentation in the case of the Santa Rosa 

 leucocephalus affects parts of the body which can play no part in 

 concealment (p. 72), though he is inclined to think that 

 ' pigmentation throughout the body depends, in part, on a 

 common genetic basis. Thus selection with reference to 

 coat-colour could bring about changes in the pigmentation of 

 invisible parts.' 



Eggs of Yellow Wattled Lapwing. 



A very interesting case of protective coloration of the eggs 

 of a plover has recently been described by Stuart Baker (1931, 

 p. 249). The Indian Yellow Wattled Lapwing (Lobipluvia 

 malabarica) nests on bare soil, usually in quite exposed situations. 



