204 : Directive Coloration in Animals. 
may be useful in more than one way. For example, the ears of the 
jack-rabbit may serve to notify his fellow of his presence at a dis- 
tance, and when close at hand they, doubtless, are very expressive 
of the bodily position and mental condition of their owner. 
Looking now over the whole animal kingdom, so far as the more 
comprehensive works on natural history and more careful descrip- 
tions of our local faunas will allow us, we find a vast number of 
spots and lines about the head, shoulders, flanks and tails of animals 
belonging to all the so-called sub-kingdoms; and we find in our 
theory a plausible explanation, in harmony with the workings of 
natural selection. 
We find some, however, which, while properly associated with the 
cases already described, do not come under either of them exactly. 
Hitherto we have considered where only a few individuals were con- 
cerned and only in the casual relations of ordinary life. There are 
cases where large numbers herd together, oftentimes moving rapidly 
in crowded phalanx or disorderly mass, where each must closely 
regulate his movements according to the action of his immediate 
companions if he would avoid collision and injury. Not only is 
this important in diurnal travels, but in the nocturnal bivouac, and 
especially in a stampede at night. In this way we may explain the 
stripes of the zebra, koodo, etc., and the numerous bright and ex- 
tended markings on the various African antelopes. It would seem 
that the greater and more ferocious carnivores of the tropics might 
have an influence to intensify these features. The bright markings 
of hyenas and the hunting-dogs are other conspicuous examples, 
traceable to quite a different combination of circumstances. 
striking marks, which we have noted under another head, may be 
also helpful in the way just described. For instance, the markings 
about the head and tail of wild geese and ducks and the black tips 
of the wings of pelicans may assist them much in keeping their 
regular order of flight ; so, also, the markings upon sparrows, which 
are helpful in the ways already indicated, during their summer-life 
may also be of service during their griion by helping them to 
harmonize their movements. ; 
It will be seen by a moment’s thought that most of the markings 
helping to show the position of the body may be of pre-eminent 
value during courtship, especially during thesupreme moments of col- 
tion. Is would not be strange if this advantage might havea tendency 
