30 THE NATURALIST IN AUSTRALIA. 
travel underground for from a few feet to many yards at a depth of not more than 
two or three inches below the surface, its presence and position at such times being 
revealed by the raising and cracking of the surface of the sand. All efforts to keep 
the animal alive for a longer period than three or four days have so far failed, the 
chief difficulty being apparently the food question. The remains of ants were found 
in the intestines of the first example dissected, and another specimen, while in 
captivity, is reported to have devoured one of the coleopterous grubs that burrow 
into and feed upon the roots of the acacia trees, thus demonstrating its normal 
insectivorous predilections. Not improbably, as is the case with the Echidna, as 
observed by the author, the favourite food is the tender larval and nymph forms of the 
ants that would have to be sought for underground, either by burrowing or by the 
scratching away of the superimposed earth’s surface. The experiment of placing 
adult ants with Notoryctes as a tentative food supply was by no means successful, 
the animal itself, according to Dr. Stirling, apparently running the greater risk of being 
eaten. It is much to be feared, under the circumstances so far recorded, that but 
little chance exists of this interesting little marsupial being established as a permanent 
tenant of the London Zoological Gardens. 
Of the remaining terrestrial vertebrate fauna of Australia, it will hardly be 
anticipated that any group would possess the remarkable individuality that is exhibited 
by the Class mammalia.. Numbers of birds systematically migrate, while reptiles, 
amphibia, and their ova can be transported on floating driftwood. As a conse- 
quence, we find a very considerable infiltration of Indo-Malay representatives of each 
of these classes, in the northern, or tropical, Australian districts more especially. 
The highly characteristic Monitors or Varani, the largest of Australian Lacertide, 
popularly called “Goohannas,” are thus found to be generically identical with forms 
inhabiting India and North Africa; while a water-frequenting species, Varanus 
salvator, growing to a length of six or seven feet, is specifically the same as the 
Indian and Malay type. There are a number of smaller forms, such as Geckos, 
Skinks, and other lizards, which possess a similar tropical Indo-Australian distribution. 
Australia, at the same time, produces several very remarkable Lacertilian types that 
are found nowhere else outside its limits, as is made evident in a succeeding chapter 
that is specially devoted to representative members of this animal group. Concerning 
prehistoric types, it is of interest to record that Australia formerly produced species of 
Monitors or Varani, and their allies, that are estimated to have been three or four times 
larger than any existing species. One of these, Megalania prisca, was at least 
