.30 
The Queensland Naturalist. 
July, 1925 
hip:her form.s — and in this connection, especially on the 
side of ecology, much remains to be done. The evidence 
.available at present in inconclnsive. 
The invertebrate fauna possess deeper interest still, 
as it may be concerned also with ]n*oblems of distribution 
long antedating these. The Phreodrilidae, I think, pre- 
sent very strong evidence for intercontinental associa- 
tions in tlie youthern Hemisphere — possibly in Permo- 
( 'arbonif erous times. 
My object will have been achieved in this address, 
if T have at least interested some in the problems of the 
Australian invertebrate fanna. and have awakened in- 
terest in others in the problems of .AnstraTlan Natural 
History in general. 
0 
A NOTE ON THE USE OF CYOAD WOOD FOR 
BRAKE-BLOCKS. 
By Prof. S. B. J. Skertchly (Molendinar.) 
The timber-getters on onr mountains are a fine race, 
after my own heart. Their calling demands unusual 
skill ; it is no fooPs job to negotiate a team of 16 buHocRs 
hitched to a log-laden truck, through forest and scrub 
whore no roads be, down slopes like ehureh roofs. Life 
and property hang upon the grip of the brakes, and for 
brake-blocks nothing is so good as cycad wood (Macro- 
zamia Denison! ). They call the trees match-box trees 
(from the use they make of the hollowed nuts), and 
zamia, a term that has illicitly usurped the legitimate 
word Cycad. Hardwood is quite useless for brake-blocks. 
It simply polishes, ‘‘becomes greasy,’’ .smokes and col- 
lapses. Soft\voods are better, but at a pinch they also 
‘^smoke” and break up, whereas cycad wood “woolies 
up,” as they say, and grips. Even it fails and goes to 
pieces in wet weather. Now this “woollying up” is the 
secret of its supremacy, and comes about in this wise. 
The woody zone or xylem (only 0.40 in. in my 10 
inch section), is broken into spurious “annual rings’ 
by the intermittent cambium layers, which, though they 
