238 



BURRKLL. 



making the excavation, which is apparently the female platypus only, since such 

 small-sized apertures would doubtless prove tight fits for full-grown males. The 

 size and shape of the tunnel is usually in keeping with thai of the occupant in a 

 normal crawling position, but there is some slight variation of the measurements 

 throughout the tunnel. 



The nest-cavity also varies in size and shape. One which 1 measured was 

 almost perfectly round, and a stick nine inches long could he just moved about in 

 it in every direction Other cavities 1 examined were much larger and differently 

 shaped; they were usually oval and always wider than high, and measured about 

 twelve by eleven inches. The blind ends leading off from the main tunnel, or 

 "Pug Pits" as 1 call them, are apparently merely cavities from which the female 

 platypus has scratched out the soil with which to pug her burrow; they may also 

 accommodate some id' the soil again when she removes it as she passes to and fro 

 along the burrow. There is always a section of pug (dose to the entrance to the 



-Platypus burrow fifty feet in total length 



( )] 02, entrances. 



nesting-chamber, and one finds what appears to he a second cavity or blind oft-set 

 from the nesting cavity proper. This is evidently only a pug-pit, though it may 

 also provide the mother platypus with room to turn in without unnecessarily dis- 

 turbing her young ones, or to rest in. The other pug-pits may possibly serve to 

 enable the young platypus to pass each other should they meet within the subway, 

 or to allow the mother to turn comfortably within the narrow tunnel. They 

 may even serve as get-aways from enemy invaders, though 1 have observed that 

 a nesting female does not desert her nest until the final plugged partition near 

 the nest itself is broken through. And since it has taken at least an hour t I 

 unearth some of the nests we have investigated, it would seem that the females 

 within them must have had ample time to leave their nests and avail themselves 

 of these cavities had they so desired. I therefore believe my first suggestion ac- 

 counting for the presence of these cavities to be the most reasonable. 



