COLORATION 61 



of the opposite sex belonging to the other closely allied 

 species. 



All these facts are fairly conclusive that there is nothing 

 in the theory so far as sexual recognition is concerned. That 

 there is also very little in the theory as regards ordinary 

 or non-sexual recognition, we have no doubt. A roan ante- 

 lope, for instance, has bold face markings — an eland, in some 

 of its forms, none; but there is evidently no more difficulty 

 about recognition in one species than in the other. Dewar 

 and Finn believe that the rabbit's white tail is of no use, and 

 advance substantial reasons why it cannot serve as a warning 

 to other rabbits. Nevertheless, to us it does seem as if a con- 

 spicuously exhibited white tail must serve some functional 

 purpose of advertisement where there is the kind of display 

 that we see in the various hares, the white-tailed deer, and 

 the antelope squirrel. Mr. Seton produces facts to show 

 that it may serve as a guide to the young. The prong- 

 buck of America does, when excited or curious, raise the 

 hair on the white rump with a chrysanthemum effect, so 

 that it flashes in the sunlight; and it is possible that this 

 may enable the pronghorns to recognize one another at a 

 distance of a mile or two — although, as their bulging, tele- 

 scopic eyes are better than those of any other American 

 game, they can probably recognize one another's ordinary 

 markings by vision at such a long distance that the posses- 

 sion of another method of recognition seems a matter of 

 surplusage. Moreover, Mr. Nelson's exceedingly inter- 

 esting study of one species of southern jack-rabbit seems to 

 prove beyond question that, for whatever purpose, the 

 animal does deliberately make use of directive coloration. 

 This jack-rabbit is concealingly colored when crouched 



