26 THE AMERICAN NATURALIST. [VoL. XXXIV. 
the water holes where they have survived the dry season. 
Insects increase with the vegetation on which they feed, and the 
region is invaded by numerous birds which find their favorite 
food. Even rodents and marsupials immigrate sometimes in 
vast numbers from the surrounding regions. 
But soon this brief season is past, and only the hardiest and 
those with special equipment to endure the ensuing drought and 
extremes of temperature survive the long dry season. 
There was little opportunity for collecting specimens, except 
for an hour or two each day, when halting for food and water. 
If a rare lizard were seen hurrying away as the march was pro- 
ceeding, before the unwilling camel could be compelled to fall 
back from its companion and kneel for dismounting, the agile 
lizard had made good its escape. Thus, only the twenty days of 
“spelling” in camp out of 125 days in the field were really 
available for taking specimens. 
Besides several orders of invertebrates which had not been 
worked over when the report was published, there were 603 
species of animals collected by the expedition, of which 171 
species were new to science. The following is Professor Spencer's 
table of species collected : 
Mui No. oF O. OF No. oF NEW 
GENERA. SPECIES, SPECIES. 
CAFmUVOLIR eea S 7 SS I I [e] 
Chopra a o re 2 2 o 
ol. RAM aE aon RSEN 3 i II 3 
Mamupaha 8) a . —- 16 24 6 
Monotremata - . oo a I I o 
C aa i 83 100 5 
Reptilia 33 44 12 
Amphibia 4 6 I 
: 5 8 5 
Mollusca . 20 38 2I 
Arthropoda - 229 357 117 
Vermes . . I I I 
398 593 HE 
Several interesting observations on the fauna and flora of the 
center may be noted. The characteristic plants have their sur- 
