AQUATIC ANIMALS FROM HANNAN’S LAKE. 
47 
Aquatic Animals from Hannan’s Lake, Kalgoorlie. By 
W. B. Alexander, M.A. (Read September 9th, 1913.) 
On August 9th, 1913, I visited Hannan’s Lake, my special 
object being to look for Phyllopods, of which several species have 
been obtained previously in that neighbourhood. 
Close to Lakeside station I found a small pond which appeared 
to be supplied from a pipe, presumably with water from Mundaring 
Weir. The water was very turbid owing to the breeze which 
was blowing creating waves, which stirred up the muddy bottom. 
In the pond I observed numerous tadpoles, and obtained two 
specimens of a species of Estheria* and ten of .1 pus attslraliensis, 
Spencer and Hall (nine females and one male). 
A sample of the water which I obtained has been analysed 
for me by .Mr. E. S. Simpson, Chemist and Assayer to the Geo- 
logical Survey, to whose kindness I am much indebted. He re- 
ports that it is perfectly fresh potable water, the total solids 
contained being onlv 0.05 per cent, and the chlorine only 0.01 
per cent. 
In the bed of Hannan’s Lake itself water was standing in a 
number of depressions round the old workings of the Hannan's 
Public Crushing Battery. In the largest of these was a con- 
siderable pond whose water appeared to be four or five feet deep, 
the depression in which it was standing being largely artificial. 
In this pond I noticed a few large tadpoles, and obtained 
the larva of a dragon-fly. The water was teeming with a small 
brown Cladoceran, and I captured a male and a female of an 
Apus, which struck me at once as being different from those 
I had just obtained from the other pond. They proved to be 
examples of Apus gracilis. Wolf, the only previously known 
specimens of which were obtained by Drs. Michaelsen and Hart- 
meyer on July 1st, 1905, in a pond of slightly saline water in a 
dam near Hannan's Lake. | Dr. E. Wolf states that the water 
was sufficiently fresh to be used for cattle to drink. 
He remarks, “ This record is certainly remarkable, since it 
was not previously known that any species of Apus could live in 
saline water.” He also expresses surprise at the occurrence of 
the animals in the winter, since in most localities they prefer 
warm water. 
As to the second point, it is obvious that Apus could hardly 
exist in Australia at all, unless it took advantage of the winter 
rains, since it appears to be confined to small ponds which under 
natural conditions are not present in the summer. 
* Since named Cyzicus ruja, Dakin. (See P.Z.S. 1914 11 p, 301). 
f There are specimens in the W.A. Museum from Lake Violet, Wiluna. 
