3 
hunted animals like gazelles etc. have promin¬ 
ent eyes that enable them to see the slightest 
movement all round them, frogs, crocodiles, 
hippos etc., that spend most of their time in 
the water have eyes placed high up on their 
heads so that they can submerge their bodies, 
but keep their eyes and noses above water. 
Telescopic, Bi-focal, compound, and single eye 
elements (the ocellus) were shown and explained. 
After the talk Mr. Pearse answered several 
questions. There was a large attendance of 
Juniors and Seniors ani much interest was 
shown in the subject. 
FIELD IvORK . 
The .Tasmanian Biological Survey Is doing 
good work for the State by collecting, examining 
and recording all forms of life on land and in 
the waters in and around Tasmania. It is a big 
undertaking, and the Committee needs helpers. 
One valuable form of investigation that Field 
Naturalists could undertake is a survey of a 
definite area - an Ecological Survey. If you 
own an acre or two of land you would start by 
making a complete record of every species of 
plant living in the area throughout the year, 
then you could do the same with the insects, 
and other forms of life in turn, until you 
have a complete record of the plants, insects, 
mammals, birds etc. that are to be found within 
the boundary. This type of record is of greater 
value than making a collection of a few plants 
or insects, especially if accurate observations 
are carried out for several years. In every 
area will be found a community of organisms 
depending more or less upon each other, and that 
a certain balance is maintained between the 
various species so that the community is able to 
keep going. Some very interesting economic 
facts have been discovered through this s tudy 
of life - communities. 
