84 
Without a thorough knowledge of the conditions under which 
the Alga occurs in the Maitland district, it is difficult to say 
what steps should be taken with a view to its destruction. Under 
the circumstances I can only make a few suggestions which might, 
if carried out, tend to reduce its numbers. 
In the first place it is a well known fact that the Rotifera or 
Wheel-animaculse feed on small unicellular Alga? such as the one 
in question. The Unio or Fresh -water Mussel might also be tried, 
its introduction would not be injurious to the water supply. 
But I consider the best plan would be to take advantage of the 
resting stage of the plant, and engage a staff of men to skim the 
surface of the water. With suitable wire gauze frames vast 
quantities might be collected and destroyed. If this method 
were adopted for several seasons in succession the organism might 
ultimately be eradicated. The following are a few of the more 
important works in which this Alga is dealt with : — 
Chlamydomonas pulvisculus , Ehrenberg ; Die Infusions thierchen, 
1838, p. 64. 
Chlamydomonas pulvisculus, Pritchard; Infusoria, 1861, p. 521, 
pi. 18, f. 40, 51 -54. 
Chlamydomonas pulvisculus , Cooke ; British Freshwater Algse, 
1882-4, p. 56, pi. 21, f. 3, 
Chlamydomonas pulvisculus , Bennett & Murray ; Handbook of 
Cryptogamic Botany, 1889, pp. 186, 299, 300, 409, 417, 419. 
I have the honor to be, 
Your Obedient Servant, 
Thomas Whitelegge. 
SPECIMENS OBTAINED ON A DREDGING TRIP IN 
PORT JACKSON, SATURDAY, 30th MAY, 1890. 
As an instance of the very extensive Marine Fauna of Port 
Jackson, the following list of the various species obtained in one 
day’s dredging is given. The specimens have been determined 
