ON THE DEVELOPMENT OF LICHENOPORA VERRUOARIA. 79 
I shows the end view of a young colony, similar to fig. 1, 
Plate 7. The space or zoccium A is uppermost, while B 
and c are nearer to the seaweed. Assuming it to be possible 
for the whole tube shown in I to roll over, it is obvious that it 
can do so in the direction shown by either of the two arrows. 
Should it roll to the left, we shall have the condition shown in 
II, where a and c have come to the upper surface, while B alone 
is left in contact with the seaweed. III shows the result of 
the rotation of I to the right. 
Returning to Pl. 7, fig. 1, it will be understood that the 
young colony is attached by the flat surface of its plano-convex 
disc, as well as by the flattened wall of the zoccia 2 and 3. 
This precludes any actual rotation of the parts already deve- 
loped, but it does not preclude an alteration in the relative 
position of 1, 2, and 3, as the colony increases in length. This 
it does in such a way as to assume the position which would 
be arrived at if it at first grew quite symmetrically, but subse- 
quently experienced a rotation of the common mouth of the 
tube, while leaving its proximal end unaltered. In other 
words, the zoecium 1 may either grow to the right or to the 
left, as shown in IV and V of the woodcut, the other two 
zocecia experiencing a corresponding change of position. A 
colony in which 1, as seen under the compound. microscope, 
has grown to the right, will be described as “ right-handed ” 
(IV), while a ‘ left-handed” colony has the appearance of V 
in the woodcut. 
It is obvious that a cross-section of either IV or V, imme- 
diately above the constriction which marks the passage of 1 
into the disc, will have the appearance of I; while a section 
taken more distally will show the first zocecium (1) in the 
position of a in IT or III, according as we are dealing with a 
*‘ right-handed ” or a “left-handed” colony. It is clear that 
the zocecium 3 in IV corresponds with B in II; while 3 in V 
corresponds with cin IIT; and the object of giving different 
symbols to these zowcia in 1V and V is to call attention to the 
fact that the individual properties of the zoccia in the older 
colony depend on the direction in which the primary zocecium 
