IN DEFENSIVE COLORATION 313 



blance. The neutralization of shadow is well seen in the 

 predaceous Carnivora, and, in many of them, characteristic 

 details are depicted on the shadowless and ghost-like 

 surface of their general ground-colour ; vistas of upright 

 stems on the tiger, effects of light and shade, even, 

 it is said, pin-hole images of the sun as cast by minute 

 interstices between leaves, on arboreal species. Adjust- 

 able Resemblance in aggressive species, such as the 

 Chameleon, Cuttlefish, and many Crustacea, is probably 

 chiefly protective in function, but there can be little doubt 

 that it is aggressive as well. Chamaeleo pumilus, slowly 

 moving to within striking distance of its alert and active 

 prey, is probably aided by colour adjustment and the 

 neutralization of shadow. The Seasonal Changes of 

 northern forms are just as characteristic of the predaceous 

 Arctic Fox and Ermine as of the Alpine Hare, Lemming, 

 and Ptarmigan. 



C. Allocryptic or Adventitious Protective and 

 Aggressive Resemblance. 



Concealment is often effected by means of a covering 

 of foreign objects. Such forms are of course hidden in 

 any environment. When sedentary they are covered 

 with local materials, when wandering they have the 

 instinct to reclothe. The great majority of examples are 

 Alloprocryptic, such as the little English crab Stenor- 

 rhynchus phalangium* \ which decks itself with pieces of 

 seaweed ; but examples of Allanticryptic Resemblance 

 are well known. It will be sufficient to mention two 

 species : — 



1. The large Brazilian frog Ceratophrys cornuta* 

 which squats in a hole in the ground and covers its back 

 with earth, the exposed parts harmonizing with the 

 surroundings. The frog remains thus motionless and 

 concealed, waiting until some small animal approaches or 

 even walks over it. 



2, The ant-lion (Myi'ineleon) larva, buried in fine sand 

 or dust, at the bottom of its crater-like pit. 



Allocryptic Resemblance may be both protective and 

 aggressive at one and the same time. 



