pipers; alighting again, daintily and quickly, on the first new branch that 

 suits them, — or sometimes wheeling and returning to their former perch, — and 

 instantly they are changed back into lifeless knots. 



When a normal obliterative shading does exist on bats, as is the case with 

 a good many species, its main service is probably the making them addition- 

 ally elusive in their crepuscular and nocturnal flights. The shading is usually 

 rather slight, from deep brown to paler grayish, but it sometimes reaches 

 dingy or even pure white. 



There is no other important order of mammals in which obliterative shad- 

 ing and disguising coloration in general play so small a part. The compara- 

 tively few other beasts whose costumes are notable for their nonconformity 

 with the predominant rules of obliterative coloration, may be grouped as fol- 

 lows : They are either strictly nocturnal (some of the smaller camivora, and also 

 some beasts which are large and fearless, but only semi-predaceous, e. g., many 

 bears), or fossorial, living almost wholly underground (some edentates and 

 moles), or arboreal, skulking (wont to take refuge in thick coverts and dense 

 shade), and also acrobatic, often standing erect, and thus exposing their un- 

 dersides to full light (e. g., some of the apes and monkeys), or protected by 

 some extraordinary defensive equipment, so that they are in little or no dan- 

 ger from the attacks of predatory creatures (e. g., hedgehogs, porcupines, 

 echidnas, pangolins, and some armadillos), or they enjoy a like security by 

 virtue of their gigantic bigness, and, being herbivorous, have no need of ob- 

 literative coloration to aid them in securing their food (e. g., elephants, rhi- 

 noceroses, and hippopotami). Compared with the vast roll of the species 

 equipped with full obliterative shading, the exceptions contained in these five 

 classes are numerically insignificant. But they are important as bearing 

 further weighty witness to the beautiful completeness of the correlation be- 

 tween animals' modes of life, defensive and offensive armaments, and dis- 

 guising-coloration. The hedgehogs, porcupines, and echidnas (belonging 

 respectively, in the sequence named, to the orders Insectivora and Rodentia 

 and the order Monotremata of the strange subclass Ornithodelphia) are all 



