580 
fusiform, others rhomboidal, others with pointed appendages. The 
variety of forms is very great, and it is possible that this may be 
partly owing to the effects of frost on the cells. On the spontaneous 
Fig. 4. 
separation of the bark, the mesophlceum was seen to consist of dis- 
tinct plates of a more or less quadrilateral form, with some of the 
edges concave and others convex, a part in the centre indicating the 
connection with the leaf, along with which it is detached. In Fig. 
5 a leaf is shown with a mesophloeal plate at- 
tached. 
The endophloeum, liber or inner bark, is of a 
fibrous nature, and consists of elongated woody 
tubes. 
The appearances presented by the outer and 
middle bark of Araucaria imbricata bear a 
marked resemblance to those exhibited by cer- 
tain fossils included in the genera Sigillaria and 
Lepidodendron. The sculpturesque markings 
on the stems of these fossil plants have induced 
geologists to look upon them as allied to the 
ferns and lycopods of the present epoch. But 
it is evident, from the specimens of Araucaria 
now laid before the Society, that much caution is 
g required in making this determination. Other 
points of structure must be examined before 
a proper decision can be formed ; when, for instance, the pre- 
sence of scalariform tissue, or of punctated woody tissue has 
been satisfactorily shown under the microscope, we are entitled to 
