80 MORE REMARKS ON FLORA AND FAUNA 



snakes chiefly ; but as the females are not provided with 

 spurs, these appendages can scarcely be intended for 

 defensive purposes. There are glands at the bases of the 

 spurs, but I could never discover any fluid, poisonous or 

 otherwise, and my theory that these spurs are in process 

 of evolution, or devolution, is probably the correct explana- 

 tion of their presence on the animal. 



The duck-bill is a strong swimmer, and this is a singular 

 circumstance considering that the animal inhabits small 

 bodies of water only, and carefully eschews currents and 

 running water generally. In swimming it assumes the 

 ordinary recumbent attitude, but it has a habit of floating 

 motionless for a long time at a stretch, and then it assumes 

 a vertical position with its head and beak held upright. In 

 this position duck-bills have a very extraordinary appear- 

 ance, like the tops of so many small posts appearing above 

 the surface of the water. The slightest noise is sufficient 

 to cause them to disappear instantly by sinking beneath 

 the surface of the water, where they swim to the submerged 

 entrances to their burrows and take refuge within. 



This habit is well known to the blackfellows who, 

 having alarmed a colony of duck-bills and driven them to 

 their retreats, proceed to dig them out with their roughly 

 constructed paddles. The course of the burrow is ascer- 

 tained by driving a pointed stick into the ground ; and 

 when the direction of it is satisfactorily ascertained, holes 

 are dug at intervals of four or five feet until the nest 

 chamber is reached at a distance of three or four feet 

 beneath the surface of the ground, where the animal is 

 found curled up with fright. It makes no attempt to 

 escape, and one sharp rap on the head kills it, for it is 

 not so tenacious of life as the echidna. 



The skeleton of the duck-bill is very reptilian in 

 general characteristics ; the arrangement of the bones 

 being, in several parts, similar to that found in the 

 skeleton of a lizard. The young are suckled through 

 lacteal-pits and not by means of teats ; but this peculiarity 

 is common to many of the wallabies and kangaroos as well 

 as to the monotremata. They are nearly always two in 



