m THE SERVICE OF TAILS 89 



support of this that the tails of the horse, zebra, 

 and other equines, and such large horse-like ante- 

 lopes as the gnus, had remained long, and often 

 really bushy, because these animals were kickers, 

 and able to prevent with their heels any attempt to 

 bite this long appendage. A natural corollary of 

 this would be the fact that the secretive habits of 

 the mice, which live in holes, are mainly nocturnal, 

 and are attacked by large animals only by being 

 pounced upon or dug out, rendered the length of 

 their tails neither helpful nor harmful to them so 

 far as enemies are concerned ; having probably no 

 more to do with their means of defence than have 

 their large ears nor so much ! 



Let us, after this digression, return to the main 

 line of our story, and ascertain further how certain 

 of these appendages serve as weapons, and are 

 even armed to that end. 



In the geological long-ago there lived flying 

 saurians with long tails ; and one of these, de- 

 scribed by Professor Marsh, had spines two feet 

 long on the side of its tail, running outward and 

 backward. 



A fish more unpleasant to meet than even this 

 long-departed animal is well known along our 

 Eastern coast, as well as in many other parts of 

 the world, under the name of sting-ray, or stinga- 

 ree. The rays (or skates) are flat, triangular-shaped 

 brutes, allied to the sharks in structure ; and they 

 have slender, whiplash-like tails. That of the 



