188 



72 mm., and the large gut some 20 mm.; but in Leporillus 

 jonesi the small gut is 57 mm., while the large gut measures 

 40 mm. The faceal pellets are more rounded in form than 

 are those of the members of the genus Rattus, and they are 

 deposited in gropus. 



The rat is a nest-builder, and, so far as 1 have seen, 

 never excavates burrows for itself; in captivity, it shows no 

 desire to burrow, or even to scratch into the earth. In the 

 islands, a burrow is almost always found beneath the nest, 

 and into the burrow the rat will readily retreat; but the 

 burrow is always one excavated beneath the nest by a penguin 

 (Eudyptula minor) or a mutton bird (Pujfinus tenuirostris). 

 There almost seems to be a measure of symbiosis in the economy 



Fig. 7. 



Leporillus jonesi. The caecum. 



A. is the entering small intestine and B. the emerging 

 large intestine. Natural size. 



of the rats and the penguins, for practically every nest which 

 is found on the northern platform of the islands has a penguin's 

 burrow beneath it. It is a remarkable fact that mutton 

 birds, penguins, rats, bandicoots, and the black tiger snakes 

 will all bolt into the same hole when alarmed. 



In some of the rats' nests an enormous amount of material 

 is collected, and these large nests appear to lodge a colony. 

 Upon the northern side of the eastern island, and high up on 

 the cliff, is such a nest; and it is probable that its foundation 

 consists of a deserted nest of the sea eagle, the rats having 

 invaded it from below. Upon the flat tops of the islands, the 

 nests are usually composed of dried herbage, and contain only 



