PATTERN-BLENDING. 683 



The Jaguar (Felts oiica). — Here the pattern is laid on a back- 

 ground presenting very little oblitei-ative shading : on the back 

 are closely placed black spots ; as the ventral surface is approached 

 the spots are seen to contain a central light brown area which 

 gi-adually increases in size, whilst the surrounding dark ring 

 diminishes and on the ventral surface becomes broken up into a 

 number of separate spots irregularly arranged around the central 

 area. This central area is always somewhat darker than the 

 background and usually contains a small central black spot. 

 Viewed as a whole this rather complicated pattern (see text-tig. 

 3, 17) shows a decreasing quantity of black from above, down- 

 wards, and when blended at distance will produce a graded tone 

 similar to obliterative shading. A similar pattern is found in the 

 Ocelot [F. pardcdis) and in several varieties of the Leopard, where 

 it is often associated with an entire absence of obliterative 

 shading. 



These patterns found in the genus Felis have been considered 

 to be picture-paintings of a checkered background, for instance, 

 leaf-shadows on bare ground ; but the extreme regularity of these 

 patterns is so unlike the very irregular nature of such backgrounds 

 and so unlike the patterns which undoubtedly do simulate these 

 backgrounds, that this deduction does not appear to be well 

 founded ; especially as these patterns blend at a comparatively 

 shoi't distance, probably within the charging length of the cat : 

 and lastly, several of these animals inhabit open country. 



However, apart from this consideration, the facts remain that 

 these patterns will produce after blending obliterative shading, 

 which is otherwise not presented ; and these patterns must in this 

 respect be powerful aids in concealment. 



Sufficient examples have now been given to illustrate that this 

 method of concealment is by no means uncommonly utilised. 

 Black and white has been chiefly dealt with, but any colour can 

 be produced by the blending of patterns consisting of two or 

 more colours : examples of this are not difficult to find, for 

 instance brown is often produced by the blending of buflf and 

 black. 



Experiments were carried out to discover whether this method 

 of coloration had any advantage over an unpatterned one. If a 

 grey disc be examined in front of a series of backgrounds varying 

 from black to white, a particular background will be found against 

 which the grey disc is invisible, this being of course that back- 

 ground which is of an exactly similar tone to the disc : against 

 the other backgrounds the disc will be visible at varying dis- 

 tances. If the results so obtained be compared with those obtained 

 when a disc of black and white squares, which after blending 

 produce the same tone of grey as the original disc, is substituted, 

 it is found that the checkered disc possesses no advantage a.s 

 regards the distances at which it can be seen, over the plain disc. 

 There is, however, an exception : against the background on which 

 the plain disc is invisible, the checkered disc is of course visible 



