CHAPTER III 



EXPOSED AND CONCEALED ANIMALS 

 (PHANEROZOA AND CRYPTOZOa) 



Phanerozoic or diurnal animals are positively 

 heliotropic ; cryptozoic animals including crepu- 

 scular, nocturnal, and subterranean forms, in 

 fact all that avoid the light of day, are negatively 

 heliotropic. Flights of butterflies at high noon 

 are followed by swarms of hawk-moths and 

 noctuids at twilight. The contrast is particularly 

 well illustrated on a broad and spectacular scale 

 by the interchange of amenities between such 

 gregarious creatures as crows and the so-called 

 flying foxes or fruit-eating bats, due to their 

 homing in the same place, as may be observed 

 daily in certain favourable localities in the mari- 

 time districts of Ceylon. I recorded these facts 

 in " Spolia Zeylanica," after mentioning them 

 in a letter to the late Professor Alfred Newton 

 who expressed his appreciation of them. These 

 animals keep remarkably regular hours of work 

 and sleep, the birds foraging by day, the bats 

 by night. 



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