MAMMALS 39 



Amongst the ordinary sharply pointed, stiff quills on 

 the tail are a number of peculiarly modified quills ; 

 their stalks are very slender, but they expand at the apex 

 into a thin-walled and hollow cylinder open at the top. 

 When the tail is violently agitated these hollow cylinders 

 wag to and fro on their slender stalks, and bang against 

 each other and against the stiff tail quills, thus pro- 

 ducing a loud rattling noise. The well-known black and 

 white quills, that cover the Porcupine's body, serve to 

 make the animal very conspicuous, and as the quills are 

 really quite formidable weapons, being sharp and strong 

 and capable of penetrating the skin of an enemy such 

 as a carnivore, it seems likely that both the colouring 

 of the Porcupine and the rattling noise produced by the 

 tail are warning signals, comparable with the white 

 bushy tail of the Skunk and the rattle of the Rattle-Snake. 

 In the embryo Porcupine the developing quills are 

 arranged in longitudinal rows, so that a striped appear- 

 ance is produced a character, be it noted, of the young 

 of many mammals. 



The curious quill-less Porcupine, Trichys lipura, is pecu- 

 liar to Borneo. The following account of this animal 

 is quoted from Hose's Mammals of Borneo (p. 61) : 

 " All the upper and lateral parts of the body are densely 

 covered with flat flexible bristles of moderate length, 

 grooved on the upper as well as the lower surface. 

 Underfur very scantily represented by fine woolly hairs ; 

 and on the rump some long hair-like bristles project 

 beyond the flat ones. . . . The general tint of the upper 

 parts of the animal is brown, each spine being white 

 at the base, and brown towards the point. On the 

 sides the brown colour gradually passes into the white 

 of the lower parts." An adult measures in body-length 



