OCCURRENCE OF TERPENE TERPINENE. 533 
forms. This is also indicated by the principal chemical 
constituent in the oil being pinene. It is only in the oils 
of the more recent members of the genus that the terpene 
phellandrene is found, so that the peculiarity is noticed of 
terpinene (one of these closely agreeing terpenes) being 
found at that end of the genus which is more largely repre- 
sented in Western Australia, while the other terpene 
(phellandrene) is a characteristic constituent in the oils of 
the members of the more recent groups of the genus, or 
those which occur most abundantly in the south-eastern 
vortion of Australia. 
