236 BUREBLL. 



her young during' the daytime. On two occasions I have unearthed nests whicb 

 contained the mother and one young one, and once a female at home in a fully- 

 constructed, new nest without eggs or young. But on three occasions when I 

 have found twins, and once when triplets were discovered, neither the mothers nor 

 the fathers were on the premises. I have observed that platypus may be seen 

 feeding in the river at almost any time during the day, so I have come to the 

 conclusion that if the mother has more than one young one to supply food for. 

 she is compelled to feed during the daytime to create a sufficient milk supply. I 

 think it probable that the male platypus does not assist in providing the young 

 with food, but that the female, like the mother Echidna, gets along without his 

 assistance after copulation. 



Nevertheless, I should mention here that a full-blooded aboriginal voluntarily 

 informed me that he had seen a male platypus carrying nesting material across a 

 river and into a burrow. He said that it had two bundles which were gripped by 

 the spurs, one on either side of the tail. Though this would appear improbable, it 

 is nevertheless possible, because a platypus trails its hind-legs inertly behind witli 

 the tail when swimming quietly, Further, there is nothing to prevent a male 

 platypus from climbing a bank with its spurs so loaded, since they are not rigid 

 like those of a cock, but could be used almost as a thumb, though bent somewhat 

 in the opposite direction, It might therefore be possible for the animal to collect 

 nesting material from the ground by lifting it up with the curved spur, and then 

 clamping it to the thigh. 



But whatever be the means by which nesting material is carried to the nest, T 

 thin!: it probable f hat the jaws and horny grinders id' the platypus are brought 

 into play. One nest I examined was composed principally of sections of the liases 

 of reeds which had been flattened, and which looked exactly like shredded or 

 fuzzed bark. I examined the reeds growing on the bank near by. and also some 

 pieces which were strewn about, lint found that even their dead and decayed por- 

 tions retained their natural rounded shape. I therefore suppose that the flat- 

 ness of the reeds in the nest is caused by the animal's grinders. Though I have 

 examined over one hundred burrows of Ornithorhynehus during the past ten 

 years, 1 have not found two quite alike. They vary in their length, direction and 

 shape, their depth and their entrances, the pug-pits and nesting cavities, and the 

 quantity of pug used. The accompanying photograph (Fig. 5) illustrates a mode! 

 of a burrow which is true to scale, while I also submit diagrams of other curious 

 burrows selected from my notes to depict the shapes of different tunnels. 



The length of the burrows ranges from fourteen to fifty feet. They wend 

 either to the right or to the left, or both ways, and sometimes actually curve 

 around into a complete loop, one portion winding at least twelve inches below 

 the other. I think the platypus must know when it is approaching its own or 

 any other burrow by some sense of sound, which causes it to divert its course so 

 as to avoid the tunnel by a space of twelve inches or more. One bin row winch 

 I opened up circled round on a uniform level and terminated when it came within 

 a foot of itself. I have found another platypus burrow descending to a depth 

 of four feet in order to avoid a rabbit burrow, and then rising again to its 

 original level on the other side. I have also examined burrows which extended 

 within twelve inches of some other animal's burrow, and then either turned back in 

 the opposite direction or to the right or left of the "sounded" obstacle. 



The entrance to a platypus breeding burrow is arched above and flat below, 

 and its size varies from four to six inches in width, and three to four inches in 

 height. This is, I think, in accordance witli the size and shape of the individual 





