1921.] 
New Zealand Institute Science Congress. 
39 
Notes on the Natural Camouflage of some Marine Mollusca, by Miss 
M. K. Mestayer. 
Abstract. 
These notes on natural camouflage deal with some of the ways in which our marine 
molluscs protect themselves from their enemies. This end is achieved in two ways : either 
by the animal’s own effort, or by the shell becoming encrusted with the surrounding 
animal and vegetable life. Some measure of protection is also obtained by those molluscs 
living above half-tide, through the action of sun, wind, and rain weathering their shells 
till they closely resemble the rocks they live on. The best example of deliberate camou¬ 
flage among New Zealand molluscs is to be found in the Hauraki Gulf, at about 30 fathoms. 
It is known as the “ carrier ” shell, from its habit of cementing other shells or bits of 
stone to its own, till it looks like a heap of old shells. The commonest forms of this 
natural camouflage are those which depend on the surroundings of the shells concerned ; 
some being covered with coralline and other seaweeds, others often having their shells 
more or less hidden by small barnacles or other animal life. 
Plant-propagation, by P. Black. 
On Growth-periods in New Zealand Plants, especially Fagus fusca and 
the Totara, by Professor H. B. Kirk. 
Abstract. 
The paper dealt with the varying rate of growth at different periods of age, pointing 
out that the totara, for example, passes through a slow youth, extending for about 100 
years. During this time it makes, roughly, a diameter-growth of about 3|- in. in each 
25 years, and at 100 years it has a diameter of about 14 in. Then it enters upon 
a period of vigorous growth, and until it is 225 years old it makes rapid growth. 
A very remarkable increase is made at about 300 years ; then the increase for 25 years, 
when the tree is growing most vigorously, is about equal to the whole growth of the 
first 100 years. After this maximum rate the growth gradually slows off, until in what 
may be called the period of senescence it becomes less than that of the youth period. 
The obvious bearing of this is that trees of 100 years or so of age—that is, with a 
diameter of 12 in. or so—are about to enter upon a rapid growth-period that will make 
them among the most valuable that the earth supports. 
With regard to Fagus fusca, the black-beech (“black-birch” of settlers in the 
South), a period of maximum growth is found at about 75 years. But the growth even at 
this period is only about one-third of that made by the totara in its full prime. In 
the beech forest at Paradise, on Lake Wakatipu, it was found that the early growth 
of forest saplings was very much slower than that of the original forest-trees. On 
the other hand, closely crowded saplings grown in a road-clearing showed a youth 
growth more rapid than that of the original forest-trees. In competition with plants 
of their own age they have grown more rapidly by far than they could have done in 
the forest, when the fallen trees would have taken from the light that is essential. 
Littoral Plant and Animal Communities, by W. B. B. Oliver. 
A Remarkable New Mosquito, by D. Miller. 
The Popular Names of New Zealand Plants, by J. C. Andersen. 
Abstract. 
The author has compiled lists of names used by various writers from the time of 
Captain Cook onwards, showing the common names given to various plants, and showing 
when the names were first applied, and how long and how consistently they have been 
used. The cabbage-tree (Cordyline australis), for example, has nearly twenty different 
names, and many trees have a dozen or more. The tree known as Nothofagus Solanderi 
has been called “ black,” “ white,” “ red,” and “ black-heart” birch in various districts, 
whilst at the same time the names “ black-birch,” “ white-birch,” &c., have been given 
to many other trees as well, “ black-birch ” being applied to no fewer than five. The 
object of the paper was to make a list available so that scientists and others might adopt 
the same common name and avoid the-confusion that had taken place in the past. 
Ecological Problems relative to Salmonidae, by W. J. Phillipis. 
The Order Hemiptera in New Zealand, with Special Reference to its 
Biological and Economic Aspects, by J. G. Myers. 
