22 W. G. RIDEWOOD. 
except one admits that the polypides are capable of leaving their tubes and 
wandering over the surface. 
The apex of each branch of the colony is bluntly pointed, and the terminal 
eight or ten tubes have transversely terminated ends without unilateral lips, 
slightly projecting above the general surface (fig. 10). These tubes have a length 
of not more than 4 or 5 mm., but their width is the same as that of the longer 
tubes situated lower down. They are curved or bent, sometimes bent as much as 
a right-angle, and they are closely crowded. Judging from the appearance of 
the more basal parts of the branch, it would seem that the bent portions of the 
tubes are subsequently straightened out, and that the tubes themselves become 
more widely separated from one another, either by deposition of new intervening 
common test, or by expansion of that already existing, though how this can be 
effected it is difficult to conceive. The short bent tubes of the apex of the branch 
have a bulbous swelling, not smaller’ than those of the longer tubes, but they differ 
from the latter in having no hemispherical septa within them. 
In exceptionally thick pieces of the colony, e.g. a piece of 30 mm. diameter, the 
tubes are very much longer than usual, and may attain a total length of 20 to 26 mm. 
These very long tubes are mostly empty tubes, and the septa are much more 
numerous than usual, and extend over 9 to 12 mm. of the tube. The part of the 
tube occupied by the polypide up to the time of its vacating the tube is thus 
11 to 14 mm. in length. Some of the long, uninhabited tubes have the apertures 
closed, and a longitudinal section of the tube shows that the closing has been effected 
by the deposition, first of some five or six thin sheets, irregular and widely separated, 
in the mouth of the tube itself, and then several thin layers of test over the opening, 
the stratification of these layers bearing no relation to that of the layers of which 
the tube is constructed (see fig. 13). The “burying layers” are not continued over 
the lip of the tube. 
In what one may conclude to be the upright branches of the colony the tubes 
are set at the same angle to the axis on all sides, and the lips are all beneath the 
apertures of the tubes; in the horizontal and oblique branches, however, it is only 
on the lower surface that the lips are strictly towards those edges of the apertures 
which are nearest the base of the branch. The openings are few on this 
surface, most of the tubes having curved round so as to open at the sides of 
the branch. 
At the sides of such a branch the lips are so situated as to be vertically below 
the apertures of the tubes, and they are thus lateral as regards the tubes themselves 
in their relation to the whole branch. The apertures on the upper surface of the 
horizontal branch are arranged irregularly, and the terminal portion of each tube is 
set nearly at right angles to the surface of the branch. The lips of the tubes are 
mainly towards the edges which are nearest the base of the branch, but the relation 
is not constant, Further complication is introduced by the presence of the secondary 
